v2.2.3

* switch to using Context internally

* add context import

* Add smoke test to make sure enabling GSN support works

* Update test/GSN/ERC721GSNRecipientMock.test.js

Co-Authored-By: Francisco Giordano <frangio.1@gmail.com>

* Upgrade truffle

* add missing awaits

* Revert "Upgrade truffle"

This reverts commit f9b0ba9019.

.babelrc

@@ -1,3 +0,0 @@
-{
-  "presets": ["es2015", "stage-2", "stage-3"]
-}

.circleci/config.yml

@@ -0,0 +1,82 @@
+version: 2
+# 2.1 does not yet support local run
+# unless with workaround. For simplicity just use it.
+# https://github.com/CircleCI-Public/circleci-cli/issues/79
+
+aliases:
+  - &defaults
+    docker:
+      - image: circleci/node:8
+
+  - &npm_install_if_necessary
+    run:
+      name: Install npm dependencies
+      command: |
+        if [ ! -d node_modules ]; then
+          npm ci
+        fi
+
+  - &cache_key_node_modules
+    key: v1-node_modules-{{ checksum "package-lock.json" }}
+
+jobs:
+  dependencies:
+    <<: *defaults
+    steps:
+      - checkout
+      - restore_cache:
+          <<: *cache_key_node_modules
+      - *npm_install_if_necessary
+      - save_cache:
+          paths:
+            - node_modules
+          <<: *cache_key_node_modules
+
+  lint:
+    <<: *defaults
+    steps:
+      - checkout
+      - restore_cache:
+          <<: *cache_key_node_modules
+      - *npm_install_if_necessary
+      - run:
+          name: Linter
+          command: npm run lint
+  test:
+    <<: *defaults
+    steps:
+      - checkout
+      - restore_cache:
+          <<: *cache_key_node_modules
+      - *npm_install_if_necessary
+      - run:
+          name: Unit tests
+          command: npm run test
+  coverage:
+    docker:
+      - image: circleci/node:8
+    steps:
+      - checkout
+      - restore_cache:
+          <<: *cache_key_node_modules
+      - *npm_install_if_necessary
+      - run:
+          name: Unit tests with coverage report
+          command: npm run coverage
+
+      # TODO(xinbenlv, #1839): run SOLC_NIGHTLY to be run but allow it to fail.
+
+workflows:
+  version: 2
+  everything:
+    jobs:
+      - dependencies
+      - lint:
+          requires:
+            - dependencies
+      - test:
+          requires:
+            - dependencies
+      - coverage:
+          requires:
+            - dependencies

.editorconfig

@@ -0,0 +1,17 @@
+# EditorConfig is awesome: https://EditorConfig.org
+
+# top-most EditorConfig file
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.sol]
+indent_size = 4
+
+[*.js]
+indent_size = 2

.eslintrc

@@ -0,0 +1,58 @@
+{
+  "extends" : [
+    "standard",
+    "plugin:promise/recommended",
+  ],
+  "plugins": [
+    "mocha-no-only",
+    "promise",
+  ],
+  "env": {
+    "browser" : true,
+    "node"    : true,
+    "mocha"   : true,
+    "jest"    : true,
+  },
+  "globals" : {
+    "artifacts": false,
+    "contract": false,
+    "assert": false,
+    "web3": false,
+  },
+  "rules": {
+
+    // Strict mode
+    "strict": ["error", "global"],
+
+    // Code style
+    "camelcase": ["error", {"properties": "always"}],
+    "comma-dangle": ["error", "always-multiline"],
+    "comma-spacing": ["error", {"before": false, "after": true}],
+    "dot-notation": ["error", {"allowKeywords": true, "allowPattern": ""}],
+    "eol-last": ["error", "always"],
+    "eqeqeq": ["error", "smart"],
+    "generator-star-spacing": ["error", "before"],
+    "indent": ["error", 2],
+    "linebreak-style": ["error", "unix"],
+    "max-len": ["error", 120, 2],
+    "no-debugger": "off",
+    "no-dupe-args": "error",
+    "no-dupe-keys": "error",
+    "no-mixed-spaces-and-tabs": ["error", "smart-tabs"],
+    "no-redeclare": ["error", {"builtinGlobals": true}],
+    "no-trailing-spaces": ["error", { "skipBlankLines": false }],
+    "no-undef": "error",
+    "no-use-before-define": "off",
+    "no-var": "error",
+    "object-curly-spacing": ["error", "always"],
+    "prefer-const": "error",
+    "quotes": ["error", "single"],
+    "semi": ["error", "always"],
+    "space-before-function-paren": ["error", "always"],
+
+    "mocha-no-only/mocha-no-only": ["error"],
+
+    "promise/always-return": "off",
+    "promise/avoid-new": "off",
+  }
+}

.gitattributes

@@ -0,0 +1 @@
+*.sol linguist-language=Solidity

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,21 @@
+---
+name: Bug report
+about: Report a bug in OpenZeppelin
+
+---
+
+<!-- Briefly describe the issue you're experiencing. Tell us what you were trying to do and what happened instead. -->
+
+<!-- Remember, this is not a place to ask for help debugging code. For that, we welcome you in the OpenZeppelin Slack channel: https://slack.openzeppelin.org/. -->
+
+**💻 Environment**
+
+<!-- Tell us what version of OpenZeppelin you're using, and how you're using it: Truffle, Remix, etc. -->
+
+**📝 Details**
+
+<!-- Describe the problem you have been experiencing in more detail. Include as much information as you think is relevant. Keep in mind that transactions can fail for many reasons; context is key here. -->
+
+**🔢 Code to reproduce bug**
+
+<!-- We will be able to better help if you provide a minimal example that triggers the bug. -->

.github/ISSUE_TEMPLATE/feature_request.md

@@ -0,0 +1,14 @@
+---
+name: Feature request
+about: Suggest an idea for OpenZeppelin
+
+---
+
+**🧐 Motivation**
+<!-- Is your feature request related to a specific problem? Is it just a crazy idea? Tell us about it! -->
+
+**📝 Details**
+<!-- Please describe your feature request in detail. -->
+
+<!-- Make sure that you have reviewed the OpenZeppelin Contributor Guidelines. -->
+<!-- https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/CONTRIBUTING.md -->

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,22 @@
+<!-- 0. 🎉 Thank you for submitting a PR! -->
+
+<!-- 1. Does this close any open issues? Please list them below. -->
+
+<!-- Keep in mind that new features have a better chance of being merged fast if
+they were first discussed and designed with the maintainers. If there is no
+corresponding issue, please consider opening one for discussion first! -->
+
+Fixes #
+
+<!-- 2. Describe the changes introduced in this pull request. -->
+<!--    Include any context necessary for understanding the PR's purpose. -->
+
+<!-- 3. Before submitting, please make sure that you have:
+  - reviewed the OpenZeppelin Contributor Guidelines
+    (https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/CONTRIBUTING.md),
+  - added tests where applicable to test new functionality,
+  - made sure that your contracts are well-documented,
+  - run the Solidity linter (`npm run lint:sol`) and fixed any issues,
+  - run the JS linter and fixed any issues (`npm run lint:fix`), and
+  - updated the changelog, if applicable.
+-->

.gitignore

@@ -1,5 +1,44 @@
 *.swp
 *.swo
-node_modules/
+
+# Logs
+logs
+*.log
+
+# Runtime data
+pids
+*.pid
+*.seed
+allFiredEvents
+scTopics
+
+# Coverage directory used by tools like istanbul
+coverage
+coverage.json
+coverageEnv
+
+# node-waf configuration
+.lock-wscript
+
+# Dependency directory
+node_modules
+
+# Debug log from npm
+npm-debug.log
+
+# local env variables
+.env
+
+# truffle build directory
 build/
-.DS_Store/
+
+# macOS
+.DS_Store
+
+# truffle
+.node-xmlhttprequest-*
+
+.openzeppelin/.session
+
+# IntelliJ IDE
+.idea

.openzeppelin/kovan.json

@@ -0,0 +1,923 @@
+{
+  "contracts": {
+    "StandaloneERC721": {
+      "address": "0xb8cBf1CC110c42C15CEf3CA0982b812a82d99613",
+      "constructorCode": "60806040526139f3806100136000396000f3fe",
+      "bodyBytecodeHash": "33aac4411967c3463cdac9bb7d6d491c9bd9f8338aeb53d8ebe0cf054abb2508",
+      "localBytecodeHash": "16e6da0afa76f1d342939ec26b9213e99b8b707e52b930005971e9d752fdc54a",
+      "deployedBytecodeHash": "16e6da0afa76f1d342939ec26b9213e99b8b707e52b930005971e9d752fdc54a",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_address>": {
+          "id": "t_mapping<t_address>",
+          "valueType": "t_address",
+          "label": "mapping(key => address)",
+          "kind": "mapping"
+        },
+        "t_struct<Counters.Counter>": {
+          "id": "t_struct<Counters.Counter>",
+          "kind": "struct",
+          "label": "Counters.Counter",
+          "members": [
+            {
+              "label": "_value",
+              "astId": 3662,
+              "type": "t_uint256",
+              "src": "1021:14:30"
+            }
+          ]
+        },
+        "t_mapping<t_struct<Counters.Counter>>": {
+          "id": "t_mapping<t_struct<Counters.Counter>>",
+          "valueType": "t_struct<Counters.Counter>",
+          "label": "mapping(key => Counters.Counter)",
+          "kind": "mapping"
+        },
+        "t_array:dyn<t_uint256>": {
+          "id": "t_array:dyn<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "dyn",
+          "kind": "array",
+          "label": "uint256[]"
+        },
+        "t_mapping<t_array:dyn<t_uint256>>": {
+          "id": "t_mapping<t_array:dyn<t_uint256>>",
+          "valueType": "t_array:dyn<t_uint256>",
+          "label": "mapping(key => uint256[])",
+          "kind": "mapping"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_mapping<t_string>": {
+          "id": "t_mapping<t_string>",
+          "valueType": "t_string",
+          "label": "mapping(key => string)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 1222,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:8"
+            }
+          ]
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13536,
+          "type": "t_bool",
+          "src": "757:24:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13538,
+          "type": "t_bool",
+          "src": "876:25:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13594,
+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "_supportedInterfaces",
+          "astId": 5232,
+          "type": "t_mapping<t_bool>",
+          "src": "511:52:39"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "______gap",
+          "astId": 5276,
+          "type": "t_array:50<t_uint256>",
+          "src": "1244:29:39"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenOwner",
+          "astId": 11717,
+          "type": "t_mapping<t_address>",
+          "src": "886:48:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenApprovals",
+          "astId": 11721,
+          "type": "t_mapping<t_address>",
+          "src": "990:52:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_ownedTokensCount",
+          "astId": 11725,
+          "type": "t_mapping<t_struct<Counters.Counter>>",
+          "src": "1100:63:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_operatorApprovals",
+          "astId": 11731,
+          "type": "t_mapping<t_bool>",
+          "src": "1218:73:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "______gap",
+          "astId": 12258,
+          "type": "t_array:50<t_uint256>",
+          "src": "11985:29:136"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokens",
+          "astId": 12316,
+          "type": "t_mapping<t_array:dyn<t_uint256>>",
+          "src": "502:50:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokensIndex",
+          "astId": 12320,
+          "type": "t_mapping<t_uint256>",
+          "src": "622:53:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokens",
+          "astId": 12323,
+          "type": "t_array:dyn<t_uint256>",
+          "src": "736:28:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokensIndex",
+          "astId": 12327,
+          "type": "t_mapping<t_uint256>",
+          "src": "835:51:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "______gap",
+          "astId": 12656,
+          "type": "t_array:50<t_uint256>",
+          "src": "8858:29:138"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_name",
+          "astId": 12726,
+          "type": "t_string",
+          "src": "323:20:141"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_symbol",
+          "astId": 12728,
+          "type": "t_string",
+          "src": "370:22:141"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_tokenURIs",
+          "astId": 12732,
+          "type": "t_mapping<t_string>",
+          "src": "438:45:141"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "______gap",
+          "astId": 12861,
+          "type": "t_array:50<t_uint256>",
+          "src": "2891:29:141"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 1455,
+          "type": "t_struct<Roles.Role>",
+          "src": "327:27:10"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 1555,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:10"
+        },
+        {
+          "contract": "ERC721MetadataMintable",
+          "path": "contracts/token/ERC721/ERC721MetadataMintable.sol",
+          "label": "______gap",
+          "astId": 12931,
+          "type": "t_array:50<t_uint256>",
+          "src": "1055:29:142"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 1578,
+          "type": "t_struct<Roles.Role>",
+          "src": "327:27:11"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 1678,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:11"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 5445,
+          "type": "t_bool",
+          "src": "406:20:42"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 5526,
+          "type": "t_array:50<t_uint256>",
+          "src": "1487:29:42"
+        },
+        {
+          "contract": "ERC721Pausable",
+          "path": "contracts/token/ERC721/ERC721Pausable.sol",
+          "label": "______gap",
+          "astId": 13076,
+          "type": "t_array:50<t_uint256>",
+          "src": "865:29:144"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [
+          {
+            "contract": "ERC721",
+            "path": "contracts/token/ERC721/ERC721.sol",
+            "label": "_ownedTokensCount",
+            "astId": 11725,
+            "type": "t_mapping<t_struct<Counters.Counter>>",
+            "src": "1100:63:136"
+          },
+          {
+            "contract": "MinterRole",
+            "path": "contracts/access/roles/MinterRole.sol",
+            "label": "_minters",
+            "astId": 1455,
+            "type": "t_struct<Roles.Role>",
+            "src": "327:27:10"
+          },
+          {
+            "contract": "PauserRole",
+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
+            "astId": 1578,
+            "type": "t_struct<Roles.Role>",
+            "src": "327:27:11"
+          }
+        ],
+        "storageDiff": []
+      }
+    },
+    "StandaloneERC20": {
+      "address": "0xaabC7f35AF87B61148cD4047828cC7FC0707D771",
+      "constructorCode": "6080604052612b68806100136000396000f3fe",
+      "bodyBytecodeHash": "47dc17b93316f8df939ac42afd023448ba98f3c8d3f7e4240f118217a4e3020e",
+      "localBytecodeHash": "92d11f5376cafd394027eedcf15b21805f9e8e4293a286b74e8c44620c324b34",
+      "deployedBytecodeHash": "92d11f5376cafd394027eedcf15b21805f9e8e4293a286b74e8c44620c324b34",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_uint8": {
+          "id": "t_uint8",
+          "kind": "elementary",
+          "label": "uint8"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 1222,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:8"
+            }
+          ]
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
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+          "src": "1193:29:10"
+        },
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+          "label": "______gap",
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+          "type": "t_array:50<t_uint256>",
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+        },
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+          "astId": 1678,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:11"
+        },
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+          "label": "_paused",
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+          "type": "t_bool",
+          "src": "406:20:42"
+        },
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+          "astId": 5526,
+          "type": "t_array:50<t_uint256>",
+          "src": "1487:29:42"
+        },
+        {
+          "contract": "ERC20Pausable",
+          "path": "contracts/token/ERC20/ERC20Pausable.sol",
+          "label": "______gap",
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+          "type": "t_array:50<t_uint256>",
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+        }
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+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
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+          "label": "_totalShares",
+          "astId": 9654,
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+          "src": "593:28:121"
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+          "type": "t_uint256",
+          "src": "627:30:121"
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+        },
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+          "label": "_released",
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+          "type": "t_mapping<t_uint256>",
+          "src": "713:45:121"
+        },
+        {
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+        },
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+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
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+          "label": "_owner",
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+          "type": "t_address",
+          "src": "356:22:119"
+        },
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+          "astId": 9542,
+          "type": "t_array:50<t_uint256>",
+          "src": "2318:29:119"
+        },
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+          "label": "_beneficiary",
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+          "type": "t_address",
+          "src": "1148:28:36"
+        },
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+          "type": "t_uint256",
+          "src": "1278:22:36"
+        },
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+          "label": "_start",
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+          "type": "t_uint256",
+          "src": "1306:22:36"
+        },
+        {
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+          "label": "_duration",
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+          "type": "t_uint256",
+          "src": "1334:25:36"
+        },
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+          "label": "_revocable",
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+          "type": "t_bool",
+          "src": "1366:23:36"
+        },
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+          "type": "t_mapping<t_uint256>",
+          "src": "1396:46:36"
+        },
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+          "label": "_revoked",
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+          "type": "t_mapping<t_bool>",
+          "src": "1448:42:36"
+        },
+        {
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+          "label": "______gap",
+          "astId": 5059,
+          "type": "t_array:50<t_uint256>",
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+      }
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+  },
+  "solidityLibs": {},
+  "proxies": {},
+  "manifestVersion": "2.2",
+  "frozen": true,
+  "app": {
+    "address": "0xf5829D56998ccC1405B7eAbCCAC78164AF270D39"
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+  "package": {
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+  },
+  "provider": {
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+  },
+  "version": "2.2.3"
+}

.openzeppelin/mainnet.json

@@ -0,0 +1,923 @@
+{
+  "contracts": {
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+      "address": "0xC6C65338632a6E84f7D67C94EAC117571932e95c",
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+      "deployedBytecodeHash": "4fffe4f76deb208e21319fb0b5446ab2b82b2ec221097e510f0ee982a12717b6",
+      "types": {
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+          "label": "uint256"
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+          "valueType": "t_uint256",
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+          "label": "address"
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+        "t_array:dyn<t_address>": {
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+          "valueType": "t_address",
+          "length": "dyn",
+          "kind": "array",
+          "label": "address[]"
+        }
+      },
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+          "label": "initialized",
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+          "type": "t_bool",
+          "src": "757:24:154"
+        },
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+          "astId": 13538,
+          "type": "t_bool",
+          "src": "876:25:154"
+        },
+        {
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+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13594,
+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
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+          "label": "_totalShares",
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+          "src": "627:30:121"
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+        },
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+          "type": "t_mapping<t_uint256>",
+          "src": "713:45:121"
+        },
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+          "label": "_payees",
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+          "type": "t_array:dyn<t_address>",
+          "src": "764:25:121"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "______gap",
+          "astId": 9913,
+          "type": "t_array:50<t_uint256>",
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+          "type": "t_struct<Roles.Role>",
+          "src": "327:27:10"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 1555,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:10"
+        },
+        {
+          "contract": "ERC721MetadataMintable",
+          "path": "contracts/token/ERC721/ERC721MetadataMintable.sol",
+          "label": "______gap",
+          "astId": 12931,
+          "type": "t_array:50<t_uint256>",
+          "src": "1055:29:142"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 1578,
+          "type": "t_struct<Roles.Role>",
+          "src": "327:27:11"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 1678,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:11"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 5445,
+          "type": "t_bool",
+          "src": "406:20:42"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 5526,
+          "type": "t_array:50<t_uint256>",
+          "src": "1487:29:42"
+        },
+        {
+          "contract": "ERC721Pausable",
+          "path": "contracts/token/ERC721/ERC721Pausable.sol",
+          "label": "______gap",
+          "astId": 13076,
+          "type": "t_array:50<t_uint256>",
+          "src": "865:29:144"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [
+          {
+            "contract": "ERC721",
+            "path": "contracts/token/ERC721/ERC721.sol",
+            "label": "_ownedTokensCount",
+            "astId": 11725,
+            "type": "t_mapping<t_struct<Counters.Counter>>",
+            "src": "1100:63:136"
+          },
+          {
+            "contract": "MinterRole",
+            "path": "contracts/access/roles/MinterRole.sol",
+            "label": "_minters",
+            "astId": 1455,
+            "type": "t_struct<Roles.Role>",
+            "src": "327:27:10"
+          },
+          {
+            "contract": "PauserRole",
+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
+            "astId": 1578,
+            "type": "t_struct<Roles.Role>",
+            "src": "327:27:11"
+          }
+        ],
+        "storageDiff": []
+      }
+    }
+  },
+  "solidityLibs": {},
+  "proxies": {},
+  "manifestVersion": "2.2",
+  "frozen": true,
+  "app": {
+    "address": "0x2Ba1a8C7352a5B5Ea3ea3408F89e1bA7920d36CE"
+  },
+  "package": {
+    "address": "0x778dddF23Ec1B5Cb18394c6C110480CaaDB3B0f6"
+  },
+  "provider": {
+    "address": "0xfeEdcb2Bd3b5EAA52aA64063ce16ECc4987da658"
+  },
+  "version": "2.2.3"
+}

.openzeppelin/project.json

@@ -0,0 +1,19 @@
+{
+  "manifestVersion": "2.2",
+  "name": "@openzeppelin/contracts-ethereum-package",
+  "publish": true,
+  "version": "2.2.3",
+  "contracts": {
+    "StandaloneERC20": "StandaloneERC20",
+    "StandaloneERC721": "StandaloneERC721",
+    "TokenVesting": "TokenVesting",
+    "PaymentSplitter": "PaymentSplitter"
+  },
+  "dependencies": {},
+  "compiler": {
+    "manager": "truffle",
+    "compilerSettings": {
+      "optimizer": {}
+    }
+  }
+}

.openzeppelin/rinkeby.json

@@ -0,0 +1,923 @@
+{
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+      "types": {
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+          "label": "uint256"
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+          "kind": "array",
+          "label": "uint256[50]"
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+        "t_string": {
+          "id": "t_string",
+          "kind": "elementary",
+          "label": "string"
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+          "kind": "elementary",
+          "label": "uint8"
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+              "astId": 1222,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:8"
+            }
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+          "label": "_symbol",
+          "astId": 10856,
+          "type": "t_string",
+          "src": "423:22:129"
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+          "label": "_decimals",
+          "astId": 10858,
+          "type": "t_uint8",
+          "src": "451:23:129"
+        },
+        {
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+          "path": "contracts/token/ERC20/ERC20Detailed.sol",
+          "label": "______gap",
+          "astId": 10910,
+          "type": "t_array:50<t_uint256>",
+          "src": "1112:29:129"
+        },
+        {
+          "contract": "ERC20",
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+          "label": "_balances",
+          "astId": 10355,
+          "type": "t_mapping<t_uint256>",
+          "src": "809:46:126"
+        },
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+          "label": "_totalSupply",
+          "astId": 10363,
+          "type": "t_uint256",
+          "src": "938:28:126"
+        },
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+          "label": "______gap",
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+          "type": "t_array:50<t_uint256>",
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+        },
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+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:10"
+        },
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+          "path": "contracts/token/ERC20/ERC20Mintable.sol",
+          "label": "______gap",
+          "astId": 10959,
+          "type": "t_array:50<t_uint256>",
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+        },
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+          "label": "______gap",
+          "astId": 5526,
+          "type": "t_array:50<t_uint256>",
+          "src": "1487:29:42"
+        },
+        {
+          "contract": "ERC20Pausable",
+          "path": "contracts/token/ERC20/ERC20Pausable.sol",
+          "label": "______gap",
+          "astId": 11082,
+          "type": "t_array:50<t_uint256>",
+          "src": "1209:29:131"
+        }
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+          },
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+            "type": "t_struct<Roles.Role>",
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+              "contract": "ERC20",
+              "path": "contracts/token/ERC20/ERC20.sol",
+              "label": "_allowances",
+              "astId": 10361,
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+          "label": "______gap",
+          "astId": 13594,
+          "type": "t_array:50<t_uint256>",
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+        },
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+          "label": "_totalShares",
+          "astId": 9654,
+          "type": "t_uint256",
+          "src": "593:28:121"
+        },
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+          "type": "t_uint256",
+          "src": "627:30:121"
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+          "src": "1951:29:154"
+        },
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+          "label": "_owner",
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+          "type": "t_address",
+          "src": "356:22:119"
+        },
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+          "label": "______gap",
+          "astId": 9542,
+          "type": "t_array:50<t_uint256>",
+          "src": "2318:29:119"
+        },
+        {
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+          "label": "_beneficiary",
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+          "type": "t_address",
+          "src": "1148:28:36"
+        },
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+        },
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+          "type": "t_uint256",
+          "src": "1306:22:36"
+        },
+        {
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+          "label": "_duration",
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+          "type": "t_uint256",
+          "src": "1334:25:36"
+        },
+        {
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+          "type": "t_bool",
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+        },
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+          "type": "t_mapping<t_uint256>",
+          "src": "1396:46:36"
+        },
+        {
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+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revoked",
+          "astId": 4717,
+          "type": "t_mapping<t_bool>",
+          "src": "1448:42:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "______gap",
+          "astId": 5059,
+          "type": "t_array:50<t_uint256>",
+          "src": "5852:29:36"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [],
+        "storageDiff": []
+      }
+    },
+    "StandaloneERC721": {
+      "address": "0x7Fe0a0E67409503Cf795d47E1Db0c77A2220210b",
+      "constructorCode": "60806040526139f3806100136000396000f3fe",
+      "bodyBytecodeHash": "33aac4411967c3463cdac9bb7d6d491c9bd9f8338aeb53d8ebe0cf054abb2508",
+      "localBytecodeHash": "16e6da0afa76f1d342939ec26b9213e99b8b707e52b930005971e9d752fdc54a",
+      "deployedBytecodeHash": "16e6da0afa76f1d342939ec26b9213e99b8b707e52b930005971e9d752fdc54a",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
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+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        },
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+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_address>": {
+          "id": "t_mapping<t_address>",
+          "valueType": "t_address",
+          "label": "mapping(key => address)",
+          "kind": "mapping"
+        },
+        "t_struct<Counters.Counter>": {
+          "id": "t_struct<Counters.Counter>",
+          "kind": "struct",
+          "label": "Counters.Counter",
+          "members": [
+            {
+              "label": "_value",
+              "astId": 3662,
+              "type": "t_uint256",
+              "src": "1021:14:30"
+            }
+          ]
+        },
+        "t_mapping<t_struct<Counters.Counter>>": {
+          "id": "t_mapping<t_struct<Counters.Counter>>",
+          "valueType": "t_struct<Counters.Counter>",
+          "label": "mapping(key => Counters.Counter)",
+          "kind": "mapping"
+        },
+        "t_array:dyn<t_uint256>": {
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+          "valueType": "t_uint256",
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+          "kind": "array",
+          "label": "uint256[]"
+        },
+        "t_mapping<t_array:dyn<t_uint256>>": {
+          "id": "t_mapping<t_array:dyn<t_uint256>>",
+          "valueType": "t_array:dyn<t_uint256>",
+          "label": "mapping(key => uint256[])",
+          "kind": "mapping"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_string": {
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+          "kind": "elementary",
+          "label": "string"
+        },
+        "t_mapping<t_string>": {
+          "id": "t_mapping<t_string>",
+          "valueType": "t_string",
+          "label": "mapping(key => string)",
+          "kind": "mapping"
+        },
+        "t_struct<Roles.Role>": {
+          "id": "t_struct<Roles.Role>",
+          "kind": "struct",
+          "label": "Roles.Role",
+          "members": [
+            {
+              "label": "bearer",
+              "astId": 1222,
+              "type": "t_mapping<t_bool>",
+              "src": "150:32:8"
+            }
+          ]
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13536,
+          "type": "t_bool",
+          "src": "757:24:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13538,
+          "type": "t_bool",
+          "src": "876:25:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13594,
+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "_supportedInterfaces",
+          "astId": 5232,
+          "type": "t_mapping<t_bool>",
+          "src": "511:52:39"
+        },
+        {
+          "contract": "ERC165",
+          "path": "contracts/introspection/ERC165.sol",
+          "label": "______gap",
+          "astId": 5276,
+          "type": "t_array:50<t_uint256>",
+          "src": "1244:29:39"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenOwner",
+          "astId": 11717,
+          "type": "t_mapping<t_address>",
+          "src": "886:48:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_tokenApprovals",
+          "astId": 11721,
+          "type": "t_mapping<t_address>",
+          "src": "990:52:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_ownedTokensCount",
+          "astId": 11725,
+          "type": "t_mapping<t_struct<Counters.Counter>>",
+          "src": "1100:63:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "_operatorApprovals",
+          "astId": 11731,
+          "type": "t_mapping<t_bool>",
+          "src": "1218:73:136"
+        },
+        {
+          "contract": "ERC721",
+          "path": "contracts/token/ERC721/ERC721.sol",
+          "label": "______gap",
+          "astId": 12258,
+          "type": "t_array:50<t_uint256>",
+          "src": "11985:29:136"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokens",
+          "astId": 12316,
+          "type": "t_mapping<t_array:dyn<t_uint256>>",
+          "src": "502:50:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_ownedTokensIndex",
+          "astId": 12320,
+          "type": "t_mapping<t_uint256>",
+          "src": "622:53:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokens",
+          "astId": 12323,
+          "type": "t_array:dyn<t_uint256>",
+          "src": "736:28:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "_allTokensIndex",
+          "astId": 12327,
+          "type": "t_mapping<t_uint256>",
+          "src": "835:51:138"
+        },
+        {
+          "contract": "ERC721Enumerable",
+          "path": "contracts/token/ERC721/ERC721Enumerable.sol",
+          "label": "______gap",
+          "astId": 12656,
+          "type": "t_array:50<t_uint256>",
+          "src": "8858:29:138"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_name",
+          "astId": 12726,
+          "type": "t_string",
+          "src": "323:20:141"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_symbol",
+          "astId": 12728,
+          "type": "t_string",
+          "src": "370:22:141"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "_tokenURIs",
+          "astId": 12732,
+          "type": "t_mapping<t_string>",
+          "src": "438:45:141"
+        },
+        {
+          "contract": "ERC721Metadata",
+          "path": "contracts/token/ERC721/ERC721Metadata.sol",
+          "label": "______gap",
+          "astId": 12861,
+          "type": "t_array:50<t_uint256>",
+          "src": "2891:29:141"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "_minters",
+          "astId": 1455,
+          "type": "t_struct<Roles.Role>",
+          "src": "327:27:10"
+        },
+        {
+          "contract": "MinterRole",
+          "path": "contracts/access/roles/MinterRole.sol",
+          "label": "______gap",
+          "astId": 1555,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:10"
+        },
+        {
+          "contract": "ERC721MetadataMintable",
+          "path": "contracts/token/ERC721/ERC721MetadataMintable.sol",
+          "label": "______gap",
+          "astId": 12931,
+          "type": "t_array:50<t_uint256>",
+          "src": "1055:29:142"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "_pausers",
+          "astId": 1578,
+          "type": "t_struct<Roles.Role>",
+          "src": "327:27:11"
+        },
+        {
+          "contract": "PauserRole",
+          "path": "contracts/access/roles/PauserRole.sol",
+          "label": "______gap",
+          "astId": 1678,
+          "type": "t_array:50<t_uint256>",
+          "src": "1193:29:11"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "_paused",
+          "astId": 5445,
+          "type": "t_bool",
+          "src": "406:20:42"
+        },
+        {
+          "contract": "Pausable",
+          "path": "contracts/lifecycle/Pausable.sol",
+          "label": "______gap",
+          "astId": 5526,
+          "type": "t_array:50<t_uint256>",
+          "src": "1487:29:42"
+        },
+        {
+          "contract": "ERC721Pausable",
+          "path": "contracts/token/ERC721/ERC721Pausable.sol",
+          "label": "______gap",
+          "astId": 13076,
+          "type": "t_array:50<t_uint256>",
+          "src": "865:29:144"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [
+          {
+            "contract": "ERC721",
+            "path": "contracts/token/ERC721/ERC721.sol",
+            "label": "_ownedTokensCount",
+            "astId": 11725,
+            "type": "t_mapping<t_struct<Counters.Counter>>",
+            "src": "1100:63:136"
+          },
+          {
+            "contract": "MinterRole",
+            "path": "contracts/access/roles/MinterRole.sol",
+            "label": "_minters",
+            "astId": 1455,
+            "type": "t_struct<Roles.Role>",
+            "src": "327:27:10"
+          },
+          {
+            "contract": "PauserRole",
+            "path": "contracts/access/roles/PauserRole.sol",
+            "label": "_pausers",
+            "astId": 1578,
+            "type": "t_struct<Roles.Role>",
+            "src": "327:27:11"
+          }
+        ],
+        "storageDiff": []
+      }
+    }
+  },
+  "solidityLibs": {},
+  "proxies": {},
+  "manifestVersion": "2.2",
+  "frozen": true,
+  "app": {
+    "address": "0x291439E6444dAEc9e47Ae359Aa79FD1811A42679"
+  },
+  "package": {
+    "address": "0xa44bb80b290dE8a465d17B14269dF53CF0B9Bf4f"
+  },
+  "provider": {
+    "address": "0xb3356E12194d3A8a847bA76313a83718d6729eCf"
+  },
+  "version": "2.2.3"
+}

.openzeppelin/ropsten.json

@@ -0,0 +1,923 @@
+{
+  "contracts": {
+    "TokenVesting": {
+      "address": "0x87C4eE5Ce946291BCcF4ac3333f44CFfDE26f98a",
+      "constructorCode": "60806040526114e7806100136000396000f3fe",
+      "bodyBytecodeHash": "c304cafc8a928423a24501d5e106dca14630e603c16dca8d9cc17569984beaa2",
+      "localBytecodeHash": "eb377fbbff249e0f05823b8b4312d3caddce2867da947eb7a0ad85800e4db993",
+      "deployedBytecodeHash": "eb377fbbff249e0f05823b8b4312d3caddce2867da947eb7a0ad85800e4db993",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_mapping<t_bool>": {
+          "id": "t_mapping<t_bool>",
+          "valueType": "t_bool",
+          "label": "mapping(key => bool)",
+          "kind": "mapping"
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13536,
+          "type": "t_bool",
+          "src": "757:24:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13538,
+          "type": "t_bool",
+          "src": "876:25:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13594,
+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
+        {
+          "contract": "Ownable",
+          "path": "contracts/ownership/Ownable.sol",
+          "label": "_owner",
+          "astId": 9431,
+          "type": "t_address",
+          "src": "356:22:119"
+        },
+        {
+          "contract": "Ownable",
+          "path": "contracts/ownership/Ownable.sol",
+          "label": "______gap",
+          "astId": 9542,
+          "type": "t_array:50<t_uint256>",
+          "src": "2318:29:119"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_beneficiary",
+          "astId": 4701,
+          "type": "t_address",
+          "src": "1148:28:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_cliff",
+          "astId": 4703,
+          "type": "t_uint256",
+          "src": "1278:22:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_start",
+          "astId": 4705,
+          "type": "t_uint256",
+          "src": "1306:22:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_duration",
+          "astId": 4707,
+          "type": "t_uint256",
+          "src": "1334:25:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revocable",
+          "astId": 4709,
+          "type": "t_bool",
+          "src": "1366:23:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_released",
+          "astId": 4713,
+          "type": "t_mapping<t_uint256>",
+          "src": "1396:46:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "_revoked",
+          "astId": 4717,
+          "type": "t_mapping<t_bool>",
+          "src": "1448:42:36"
+        },
+        {
+          "contract": "TokenVesting",
+          "path": "contracts/drafts/TokenVesting.sol",
+          "label": "______gap",
+          "astId": 5059,
+          "type": "t_array:50<t_uint256>",
+          "src": "5852:29:36"
+        }
+      ],
+      "warnings": {
+        "hasConstructor": false,
+        "hasSelfDestruct": false,
+        "hasDelegateCall": false,
+        "hasInitialValuesInDeclarations": false,
+        "uninitializedBaseContracts": [],
+        "storageUncheckedVars": [],
+        "storageDiff": []
+      }
+    },
+    "PaymentSplitter": {
+      "address": "0x621DB5C5B8A6CFd829bDAe49D0a2c2e90797Fc38",
+      "constructorCode": "6080604052610bf2806100136000396000f3fe",
+      "bodyBytecodeHash": "f80b1634ecca81b01cd4155b3ceba5e85979d18489c685ce4bc0f3e16e50ed3d",
+      "localBytecodeHash": "4fffe4f76deb208e21319fb0b5446ab2b82b2ec221097e510f0ee982a12717b6",
+      "deployedBytecodeHash": "4fffe4f76deb208e21319fb0b5446ab2b82b2ec221097e510f0ee982a12717b6",
+      "types": {
+        "t_bool": {
+          "id": "t_bool",
+          "kind": "elementary",
+          "label": "bool"
+        },
+        "t_uint256": {
+          "id": "t_uint256",
+          "kind": "elementary",
+          "label": "uint256"
+        },
+        "t_array:50<t_uint256>": {
+          "id": "t_array:50<t_uint256>",
+          "valueType": "t_uint256",
+          "length": "50",
+          "kind": "array",
+          "label": "uint256[50]"
+        },
+        "t_mapping<t_uint256>": {
+          "id": "t_mapping<t_uint256>",
+          "valueType": "t_uint256",
+          "label": "mapping(key => uint256)",
+          "kind": "mapping"
+        },
+        "t_address": {
+          "id": "t_address",
+          "kind": "elementary",
+          "label": "address"
+        },
+        "t_array:dyn<t_address>": {
+          "id": "t_array:dyn<t_address>",
+          "valueType": "t_address",
+          "length": "dyn",
+          "kind": "array",
+          "label": "address[]"
+        }
+      },
+      "storage": [
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initialized",
+          "astId": 13536,
+          "type": "t_bool",
+          "src": "757:24:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "initializing",
+          "astId": 13538,
+          "type": "t_bool",
+          "src": "876:25:154"
+        },
+        {
+          "contract": "Initializable",
+          "path": "@openzeppelin/upgrades/contracts/Initializable.sol",
+          "label": "______gap",
+          "astId": 13594,
+          "type": "t_array:50<t_uint256>",
+          "src": "1951:29:154"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_totalShares",
+          "astId": 9654,
+          "type": "t_uint256",
+          "src": "593:28:121"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_totalReleased",
+          "astId": 9656,
+          "type": "t_uint256",
+          "src": "627:30:121"
+        },
+        {
+          "contract": "PaymentSplitter",
+          "path": "contracts/payment/PaymentSplitter.sol",
+          "label": "_shares",
+          "astId": 9660,
+          "type": "t_mapping<t_uint256>",
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+  "frozen": true,
+  "app": {
+    "address": "0x27a09abCA2c4d9F914dbC7BeA164b0e6b74Ce7a9"
+  },
+  "package": {
+    "address": "0x2a9e7B63514438906A83a1e320dBBD814D417002"
+  },
+  "provider": {
+    "address": "0xbC1628cAE5Ed8892b030864eb8e37e70d0a9594C"
+  },
+  "version": "2.2.3"
+}

.solcover.js

@@ -0,0 +1,9 @@
+module.exports = {
+    norpc: true,
+    testCommand: 'node --max-old-space-size=4096 ../node_modules/.bin/truffle test --network coverage',
+    compileCommand: 'node --max-old-space-size=4096 ../node_modules/.bin/truffle compile --network coverage',
+    skipFiles: [
+        'lifecycle/Migrations.sol',
+        'mocks'
+    ]
+}

.solhint.json

@@ -0,0 +1,11 @@
+{
+  "extends": "default",
+  "rules": {
+    "indent": ["error", 4],
+
+    "bracket-align": false,
+    "compiler-fixed": false,
+    "no-simple-event-func-name": false,
+    "two-lines-top-level-separator": false
+  }
+}

.travis.yml

@@ -1,12 +0,0 @@
-dist: trusty
-sudo: false
-group: beta
-language: node_js
-node_js:
-  - "6"
-before_install:
-  - npm i -g ethereumjs-testrpc
-  - npm i -g truffle
-script:
-  - testrpc&
-  - npm test

CHANGELOG.md

@@ -0,0 +1,70 @@
+# Changelog
+
+## 2.2.2 (2019-08-12)
+
+### New features:
+ * Facilities to make metatransaction-enabled contracts through the Gas Station Network. Backported from [#1844](https://github.com/OpenZeppelin/openzeppelin-contracts/pull/1844).
+
+## 2.2.1 (2019-07-22)
+
+### Changes:
+* Renamed package to `@openzeppelin/contracts-ethereum-package`. ([#54](https://github.com/OpenZeppelin/openzeppelin-contracts-ethereum-package/pull/54))
+
+## 2.2.0 (2019-03-14)
+
+### New features:
+ * `ERC20Snapshot`: create snapshots on demand of the token balances and total supply, to later retrieve and e.g. calculate dividends at a past time. ([#1617](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1617))
+ * `SafeERC20`: `ERC20` contracts with no return value (i.e. that revert on failure) are now supported. ([#1655](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/))
+ * `ERC20`: added internal `_approve(address owner, address spender, uint256 value)`, allowing derived contracts to set the allowance of arbitrary accounts. ([#1609](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1609))
+ * `ERC20Metadata`: added internal `_setTokenURI(string memory tokenURI)`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
+ * `TimedCrowdsale`: added internal `_extendTime(uint256 newClosingTime)` as well as `TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime)` event allowing to extend the crowdsale, as long as it hasn't already closed.
+
+### Improvements:
+ * Upgraded the minimum compiler version to v0.5.2: this removes many Solidity warnings that were false positives. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
+ * `ECDSA`: `recover` no longer accepts malleable signatures (those using upper-range values for `s`, or 0/1 for `v`). ([#1622](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1622))
+ * `ERC721`'s transfers are now more gas efficient due to removal of unnecessary `SafeMath` calls. ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
+ * `Counter`'s API has been improved, and is now used by `ERC721` (though it is still in `drafts`). ([#1610](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1610))
+ * Fixed variable shadowing issues. ([#1606](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1606))
+
+### Bugfixes:
+ * (minor) `SafeERC20`: `safeApprove` wasn't properly checking for a zero allowance when attempting to set a non-zero allowance. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
+
+### Breaking changes:
+ * `TokenMetadata` (in drafts) has been renamed to `ERC20Metadata`. ([#1618](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1618))
+
+## 2.1.3 (2019-02-26)
+ * Backported `SafeERC20.safeApprove` bugfix. ([#1647](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1647))
+
+## 2.1.2 (2019-01-17)
+ * Removed most of the test suite from the npm package, except `PublicRole.behavior.js`, which may be useful to users testing their own `Roles`.
+
+## 2.1.1 (2019-01-04)
+ * Version bump to avoid conflict in the npm registry.
+
+## 2.1.0 (2019-01-04)
+
+### New features:
+ * Now targeting the 0.5.x line of Solidity compilers. For 0.4.24 support, use version 2.0 of OpenZeppelin.
+ * `WhitelistCrowdsale`: a crowdsale where only whitelisted accounts (`WhitelistedRole`) can purchase tokens. Adding or removing accounts from the whitelist is done by whitelist admins (`WhitelistAdminRole`). Similar to the pre-2.0 `WhitelistedCrowdsale`. ([#1525](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1525), [#1589](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1589))
+ * `RefundablePostDeliveryCrowdsale`: replacement for `RefundableCrowdsale` (deprecated, see below) where tokens are only granted once the crowdsale ends (if it meets its goal). ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))
+ * `PausableCrowdsale`: allows for pausers (`PauserRole`) to pause token purchases. Other crowdsale operations (e.g. withdrawals and refunds, if applicable) are not affected. ([#832](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/832))
+ * `ERC20`: `transferFrom` and `_burnFrom ` now emit `Approval` events, to represent the token's state comprehensively through events. ([#1524](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1524))
+ * `ERC721`: added `_burn(uint256 tokenId)`, replacing the similar deprecated function (see below). ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
+ * `ERC721`: added `_tokensOfOwner(address owner)`, allowing to internally retrieve the array of an account's owned tokens. ([#1522](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1522))
+ * Crowdsales: all constructors are now `public`, meaning it is not necessary to extend these contracts in order to deploy them. The exception is `FinalizableCrowdsale`, since it is meaningless unless extended. ([#1564](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1564))
+ * `SignedSafeMath`: added overflow-safe operations for signed integers (`int256`). ([#1559](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1559), [#1588](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1588))
+
+### Improvements:
+ * The compiler version required by `Array` was behind the rest of the libray so it was updated to `v0.4.24`. ([#1553](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1553))
+ * Now conforming to a 4-space indentation code style. ([1508](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1508))
+ * `ERC20`: more gas efficient due to removed redundant `require`s. ([#1409](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1409))
+ * `ERC721`: fixed a bug that prevented internal data structures from being properly cleaned, missing potential gas refunds. ([#1539](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1539) and [#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
+ * `ERC721`: general gas savings on `transferFrom`, `_mint` and `_burn`, due to redudant `require`s and `SSTORE`s. ([#1549](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1549))
+
+### Bugfixes:
+
+### Breaking changes:
+
+### Deprecations:
+ * `ERC721._burn(address owner, uint256 tokenId)`: due to the `owner` parameter being unnecessary. ([#1550](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1550))
+ * `RefundableCrowdsale`: due to trading abuse potential on crowdsales that miss their goal. ([#1543](https://github.com/OpenZeppelin/openzeppelin-solidity/pull/1543))

CODE_OF_CONDUCT.md

@@ -0,0 +1,73 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, sex characteristics, gender identity and expression,
+level of experience, education, socio-economic status, nationality, personal
+appearance, race, religion, or sexual identity and orientation.
+
+## Our Standards
+
+Examples of behavior that contributes to creating a positive environment
+include:
+
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members
+
+Examples of unacceptable behavior by participants include:
+
+* The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Our Responsibilities
+
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.
+
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.
+
+## Scope
+
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at maintainers@openzeppelin.org. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.
+
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
+
+[homepage]: https://www.contributor-covenant.org

CODE_STYLE.md

@@ -0,0 +1,63 @@
+# Code Style
+
+We value clean code and consistency, and those are prerequisites for us to
+include new code in the repository. Before proposing a change, please read this
+document and take some time to familiarize yourself with the style of the
+existing codebase.
+
+## Solidity code
+
+In order to be consistent with all the other Solidity projects, we follow the
+[official recommendations documented in the Solidity style guide](http://solidity.readthedocs.io/en/latest/style-guide.html).
+
+Any exception or additions specific to our project are documented below.
+
+### Naming
+
+* Try to avoid acronyms and abbreviations.
+
+* All state variables should be private.
+
+* Private state variables should have an underscore prefix.
+
+    ```
+    contract TestContract {
+      uint256 private _privateVar;
+      uint256 internal _internalVar;
+    }
+    ```
+
+* Parameters must not be prefixed with an underscore.
+
+    ```
+    function test(uint256 testParameter1, uint256 testParameter2) {
+    ...
+    }
+    ```
+
+* Internal and private functions should have an underscore prefix.
+
+    ```
+    function _testInternal() internal {
+      ...
+    }
+    ```
+
+    ```
+    function _testPrivate() private {
+      ...
+    }
+    ```
+
+* Events should be emitted immediately after the state change that they
+  represent, and consequently they should be named in past tense.
+
+    ```
+    function _burn(address _who, uint256 _value) internal {
+      super._burn(_who, _value);
+      emit TokensBurned(_who, _value);
+    }
+    ```
+
+  Some standards (e.g. ERC20) use present tense, and in those cases the
+  standard specification prevails.

CONTRIBUTING.md

@@ -1,105 +1,58 @@
-Contributing to Zeppelin
+Contributing to OpenZeppelin
 =======
 
-## Design Guidelines
+We really appreciate and value contributions to OpenZeppelin. Please take 5' to review the items listed below to make sure that your contributions are merged as soon as possible. 
 
-These are some global design goals in Zeppelin.
+## Contribution guidelines
 
-### D0 - Security in Depth
-We strive to provide secure, tested, audited code. To achieve this, we need to match intention with function. Thus, documentation, code clarity, community review and security discussions are fundamental.
+Smart contracts manage value and are highly vulnerable to errors and attacks. We have very strict guidelines, please make sure to review them: ["Contribution guidelines wiki entry"](https://github.com/OpenZeppelin/openzeppelin-solidity/wiki/Contribution-guidelines).
 
-### D1 - Simple and Modular
-Simpler code means easier audits, and better understanding of what each component does. We look for small files, small contracts, and small functions. If you can separate a contract into two independent functionalities you should probably do it.
+## Creating Pull Requests (PRs)
 
-### D2 - Naming Matters
+As a contributor, you are expected to fork this repository, work on your own fork and then submit pull requests. The pull requests will be reviewed and eventually merged into the main repo. See ["Fork-a-Repo"](https://help.github.com/articles/fork-a-repo/) for how this works.
 
-We take our time with picking names. Code is going to be written once, and read hundreds of times. Renaming for clarity is encouraged.
+*IMPORTANT* 
+* Please see ["Git flow wiki entry"](https://github.com/OpenZeppelin/openzeppelin-solidity/wiki/Git-flow) for understanding how to use branches in this repository.
 
-### D3 - Tests
+## A typical workflow
 
-Write tests for all your code. We encourage Test Driven Development so we know when our code is right. Even though not all code in the repository is tested at the moment, we aim to test every line of code in the future.
+1) Make sure your fork is up to date with the main repository:
 
-### D4 - Check preconditions and post-conditions
+```
+cd openzeppelin-solidity
+git remote add upstream https://github.com/OpenZeppelin/openzeppelin-solidity.git
+git fetch upstream
+git pull --rebase upstream master
+```
+NOTE: The directory `openzeppelin-solidity` represents your fork's local copy.
 
-A very important way to prevent vulnerabilities is to catch a contract’s inconsistent state as early as possible. This is why we want functions to check pre- and post-conditions for executing its logic. When writing code, ask yourself what you are expecting to be true before and after the function runs, and express it in code.
-
-### D5 - Code Consistency
-
-Consistency on the way classes are used is paramount to an easier understanding of the library. The codebase should be as unified as possible. Read existing code and get inspired before you write your own. Follow the style guidelines. Don’t hesitate to ask for help on how to best write a specific piece of code.
-
-### D6 - Regular Audits
-Following good programming practices is a way to reduce the risk of vulnerabilities, but professional code audits are still needed. We will perform regular code audits on major releases, and hire security professionals to provide independent review.
-
-## Style Guidelines
-
-The design guidelines have quite a high abstraction level. These style guidelines are more concrete and easier to apply, and also more opinionated.
-
-### General
-
-#### G0 - Default to Solidity's official style guide.
-
-Follow the official Solidity style guide: http://solidity.readthedocs.io/en/latest/style-guide.html
-
-#### G1 - No Magic Constants
-
-Avoid constants in the code as much as possible. Magic strings are also magic constants.
-
-#### G2 - Code that Fails Early
-
-We ask our code to fail as soon as possible when an unexpected input was provided or unexpected state was found.
-
-#### G3 - Internal Amounts Must be Signed Integers and Represent the Smallest Units.
-
-Avoid representation errors by always dealing with weis when handling ether. GUIs can convert to more human-friendly representations. Use Signed Integers (int) to prevent underflow problems.
-
-
-### Testing
-
-#### T1 - Tests Must be Written Elegantly
-
-Style guidelines are not relaxed for tests. Tests are a good way to show how to use the library, and maintaining them is extremely necessary.
-
-Don't write long tests, write helper functions to make them be as short and concise as possible (they should take just a few lines each), and use good variable names.
-
-#### T2 - Tests Must not be Random
-
-Inputs for tests should not be generated randomly. Accounts used to create test contracts are an exception, those can be random. Also, the type and structure of outputs should be checked.
-
-
-### Documentation
-
-TODO
-
-## Pull Request Workflow
-
-Our workflow is based on GitHub's pull requests. We use feature branches, prepended with: `test`, `feature`, `fix`, `refactor`, or `remove` according to the change the branch introduces. Some examples for such branches are:
-```sh
-git checkout -b test/some-module
-git checkout -b feature/some-new-stuff
-git checkout -b fix/some-bug
-git checkout -b remove/some-file
+2) Branch out from `master` into `fix/some-bug-#123`:
+(Postfixing #123 will associate your PR with the issue #123 and make everyone's life easier =D)
+```
+git checkout -b fix/some-bug-#123
 ```
 
-We expect pull requests to be rebased to the master branch before merging:
-```sh
-git remote add zep git@github.com:OpenZeppelin/zeppelin-solidity.git
-git pull --rebase zep master
+3) Make your changes, add your files, commit and push to your fork.
+
+```
+git add SomeFile.js
+git commit "Fix some bug #123"
+git push origin fix/some-bug-#123
 ```
 
-Note that we require rebasing your branch instead of merging it, for commit readability reasons.
+4) Go to [github.com/OpenZeppelin/openzeppelin-solidity](https://github.com/OpenZeppelin/zeppelin-solidity) in your web browser and issue a new pull request.
 
-After that, you can push the changes to your fork, by doing:
-```sh
-git push origin your_branch_name
-git push origin feature/some-new-stuff
-git push origin fix/some-bug
-```
+*IMPORTANT* Read the PR template very carefully and make sure to follow all the instructions. These instructions 
+refer to some very important conditions that your PR must meet in order to be accepted, such as making sure that all tests pass, JS linting tests pass, solidity linting tests pass, etc.
 
-Finally go to [github.com/OpenZeppelin/zeppelin-solidity](https://github.com/OpenZeppelin/zeppelin-solidity) in your web browser and issue a new pull request.
+5) Maintainers will review your code and possibly ask for changes before your code is pulled in to the main repository. We'll check that all tests pass, review the coding style, and check for general code correctness. If everything is OK, we'll merge your pull request and your code will be part of OpenZeppelin.
 
-Main contributors will review your code and possibly ask for changes before your code is pulled in to the main repository.  We'll check that all tests pass, review the coding style, and check for general code correctness. If everything is OK, we'll merge your pull request and your code will be part of Zeppelin.
+*IMPORTANT* Please pay attention to the maintainer's feedback, since its a necessary step to keep up with the standards OpenZeppelin attains to.
 
-If you have any questions feel free to post them to
-[github.com/OpenZeppelin/zeppelin-solidity/issues](https://github.com/OpenZeppelin/zeppelin-solidity/issues).
+## All set!
+
+If you have any questions feel free to post them to github.com/OpenZeppelin/openzeppelin-solidity/issues.
+
+Finally, if you're looking to collaborate and want to find easy tasks to start, look at the issues we marked as ["Good first issue"](https://github.com/OpenZeppelin/openzeppelin-solidity/labels/good%20first%20issue).
 
 Thanks for your time and code!

LICENSE

@@ -5,18 +5,18 @@ Copyright (c) 2016 Smart Contract Solutions, Inc.
 Permission is hereby granted, free of charge, to any person obtaining
 a copy of this software and associated documentation files (the
 "Software"), to deal in the Software without restriction, including
-without limitation the rights to use, copy, modify, merge, publish, 
+without limitation the rights to use, copy, modify, merge, publish,
 distribute, sublicense, and/or sell copies of the Software, and to
-permit persons to whom the Software is furnished to do so, subject to 
+permit persons to whom the Software is furnished to do so, subject to
 the following conditions:
 
 The above copyright notice and this permission notice shall be included
 in all copies or substantial portions of the Software.
 
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 
-OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
-MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
-IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
-CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
-TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

@@ -1,89 +1,112 @@
-# Zeppelin Solidity
-[![NPM Package](https://img.shields.io/npm/v/zeppelin-solidity.svg?style=flat-square)](https://www.npmjs.org/package/zeppelin-solidity)
-[![Build Status](https://img.shields.io/travis/OpenZeppelin/zeppelin-solidity.svg?branch=master&style=flat-square)](https://travis-ci.org/OpenZeppelin/zeppelin-solidity)
+# <img src="logo.png" alt="OpenZeppelin" height="40px">
 
-Zeppelin is a library for writing secure [Smart Contracts](https://en.wikipedia.org/wiki/Smart_contract) on Ethereum.
+## OpenZeppelin Contracts Ethereum Package
 
-With Zeppelin, you can build distributed applications, protocols and organizations:
-- using common contract security patterns (See [Onward with Ethereum Smart Contract Security](https://medium.com/bitcorps-blog/onward-with-ethereum-smart-contract-security-97a827e47702#.y3kvdetbz))
-- in the [Solidity language](http://solidity.readthedocs.io/en/develop/).
+[![NPM Package](https://img.shields.io/npm/v/@openzeppelin/contracts-ethereum-package.svg)](https://www.npmjs.org/package/@openzeppelin/contracts-ethereum-package)
+[![Build Status](https://circleci.com/gh/OpenZeppelin/openzeppelin-contracts-ethereum-package.svg?style=shield)](https://circleci.com/gh/OpenZeppelin/openzeppelin-contracts-ethereum-package)
 
-> NOTE: New to smart contract development? Check our [introductory guide](https://medium.com/zeppelin-blog/the-hitchhikers-guide-to-smart-contracts-in-ethereum-848f08001f05#.cox40d2ut).
+**OpenZeppelin Contracts is a library for secure smart contract development.** It provides implementations of standards like ERC20 and ERC721 which you can deploy as-is or extend to suit your needs, as well as Solidity components to build custom contracts and more complex decentralized systems.
 
-## Getting Started
+This fork of OpenZeppelin is set up as a **reusable Ethereum Package**. It is deployed to the kovan, rinkeby, and ropsten test networks, as well as to the main Ethereum network. You can reuse any of the pre-deployed on-chain contracts by simply linking to them using the [OpenZeppelin SDK](https://github.com/openzeppelin/openzeppelin-sdk), or reuse their Solidity source code as with the [vanilla version of OpenZeppelin Contracts](https://github.com/OpenZeppelin/openzeppelin-contracts).
 
-Zeppelin integrates with [Truffle](https://github.com/ConsenSys/truffle), an Ethereum development environment. Please install Truffle and initialize your project with `truffle init`.
-```sh
-npm install -g truffle
-mkdir myproject && cd myproject
-truffle init
+## Differences with openzeppelin-contracts
+
+This package contains the same contracts as the vanilla [openzeppelin-contracts](https://github.com/openZeppelin/openzeppelin-contracts). The main difference is that _all contracts in this package are potentially upgradeable_: you will notice that no contracts have constructors defined, but use [initializer functions](https://docs.zeppelinos.org/docs/writing_contracts.html#initializers) instead. Also, this package is set up as an Ethereum package, and provides a small set of pre-deployed logic contracts that can be used directly via the OpenZeppelin SDK, without needing to deploy them again.
+
+All in all, **you should use this package instead of openzeppelin-solidity if you are managing your project via the OpenZeppelin CLI**.
+
+## Install
+
+```
+npm install @openzeppelin/contracts-ethereum-package
 ```
 
-To install the Zeppelin library, run:
-```sh
-npm i zeppelin-solidity
+## Deployed logic contracts
+
+- [StandaloneERC20](contracts/token/ERC20/StandaloneERC20.sol): ERC20 token implementation, optionally mintable and pausable.
+- [StandaloneERC721](contracts/token/ERC721/StandaloneERC721.sol): ERC721 non-fungible token implementation with metadata and enumerable extensions, optionally mintable and pausable.
+- [TokenVesting](contracts/drafts/TokenVesting.sol): tToken holder contract that can release its token balance gradually like a typical vesting scheme, with a cliff and vesting period, optionally revocable.
+- [PaymentSplitter](contracts/payment/PaymentSplitter.sol): Splits payments among a group of addresses proportionately to some number of shares they own.
+
+## Using via the OpenZeppelin CLI
+
+You can easily create upgradeable instances of any of the logic contracts listed above using the OpenZeppelin CLI. This will rely on the pre-deployed instances in mainnet, kovan, ropsten, or rinkeby, greatly reducing your gas deployment costs. To do this, just [create a new OpenZeppelin SDK project](https://docs.zeppelinos.org/docs/deploying.html) and [link to this package](https://docs.zeppelinos.org/docs/linking.html).
+
+```bash
+$ npm install -g @openzeppelin/cli
+$ openzeppelin init
+$ openzeppelin link @openzeppelin/contracts-ethereum-package
+> Installing...
+$ openzeppelin create @openzeppelin/contracts-ethereum-package/StandaloneERC20
+> Creating...
 ```
 
-After that, you'll get all the library's contracts in the `contracts/zeppelin` folder. You can use the contracts in the library like so:
+To create an instance of a contract, use the `openzeppelin create` command. As an example, you can run the following to create an upgradeable ERC20 named MyToken, with symbol TKN and 8 decimals, and an initial supply of 100 tokens assigned to the address HOLDER, with a MINTER and a PAUSER. Remember to replace $HOLDER, $MINTER, and $PAUSER with actual addresses when you run this command; you can specify more than one (or none at all) minters and pausers.
 
-```js
-import "./zeppelin/Ownable.sol";
+```
+$ openzeppelin create
+? Pick a contract to instantiate: @openzeppelin/contracts-ethereum-package/StandaloneERC20
+? Pick a network: development
+✓ Deploying @openzeppelin/contracts-ethereum-package dependency to network
+? Do you want to call a function on the instance after creating it?: Yes
+? Select which function: * initialize(name: string, symbol: string, decimals: uint8, initialSupply: uint256, initialHolder: address, minters: address[], pausers: address[])
+? name (string): MyToken
+? symbol (string): MYT
+? decimals (uint8): 18
+? initialSupply (uint256): 100e18
+? initialHolder (address): 0x90f8bf6a479f320ead074411a4b0e7944ea8c9c1
+? minters (address[]):
+? pausers (address[]):
+✓ Setting everything up to create contract instances
+✓ Instance created at 0x2612Af3A521c2df9EAF28422Ca335b04AdF3ac66
+```
 
-contract MyContract is Ownable {
-  ...
+OpenZeppelin will create an upgradeable ERC20 instance and keep track of its address in the `.openzeppelin/rinkeby.json` file. Should you update your version of the openzeppelin contracts ethereum package later down the road, you can simply run `openzeppelin update` to upgrade all your ERC20 instances to the latest version.
+
+You can also deploy a ERC721 token by choosing the `StandaloneERC721` contract when running `openzeppelin create`. Refer to the `initialize` function of each of the predeployed logic contracts to see which parameters are required for initialization.
+
+## Extending contracts
+
+If you prefer to write your custom contracts, import the ones from this package and extend them through inheritance. Note that **you must use this package and not `@openzeppelin/contracts` if you are [writing upgradeable contracts](https://docs.zeppelinos.org/docs/writing_contracts.html)**.
+
+```solidity
+pragma solidity ^0.5.0;
+
+import '@openzeppelin/upgrades/contracts/Initializable.sol';
+import '@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/ERC721Full.sol';
+import '@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/ERC721Mintable.sol';
+
+contract MyNFT is Initializable, ERC721Full, ERC721Mintable {
+  function initialize() public initializer {
+    ERC721.initialize();
+    ERC721Enumerable.initialize();
+    ERC721Metadata.initialize("MyNFT", "MNFT");
+    ERC721Mintable.initialize(msg.sender);
+  }
 }
 ```
 
-> NOTE: The current distribution channel is npm, which is not ideal. [We're looking into providing a better tool for code distribution](https://github.com/OpenZeppelin/zeppelin-solidity/issues/13), and ideas are welcome.
-
-#### Truffle Beta Support
-We also support Truffle Beta npm integration. If you're using Truffle Beta, the contracts in `node_modules` will be enough, so feel free to delete the copies at your `contracts` folder. If you're using Truffle Beta, you can use Zeppelin contracts like so:
-
-```js
-import "zeppelin-solidity/contracts/Ownable.sol";
-
-contract MyContract is Ownable {
-  ...
-}
-```
-
-For more info see [the Truffle Beta package management tutorial](http://truffleframework.com/tutorials/package-management).
-
+On our site you will find a few [guides] to learn about the different parts of OpenZeppelin, as well as [documentation for the API][API docs]. Keep in mind that the API docs are work in progress, and don’t hesitate to ask questions in [our forum][forum].
 
 ## Security
-Zeppelin is meant to provide secure, tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problem you might experience.
 
-If you find a security issue, please email [security@openzeppelin.org](mailto:security@openzeppelin.org).
+OpenZeppelin Contracts is maintained by [OpenZeppelin](https://openzeppelin.com) the company, and developed following our high standards for code quality and security. OpenZeppelin Contracts is meant to provide tested and community-audited code, but please use common sense when doing anything that deals with real money! We take no responsibility for your implementation decisions and any security problems you might experience.
 
-## Developer Resources
+The core development principles and strategies that OpenZeppelin Contracts is based on include: security in depth, simple and modular code, clarity-driven naming conventions, comprehensive unit testing, pre-and-post-condition sanity checks, code consistency, and regular audits.
 
-Building a distributed application, protocol or organization with Zeppelin?
+The latest audit was done on October 2018 on version 2.0.0.
 
-- Read documentation: http://zeppelin-solidity.readthedocs.io/en/latest/
+Please report any security issues you find to security@openzeppelin.org.
 
-- Ask for help and follow progress at: https://zeppelin-slackin.herokuapp.com/
-
-Interested in contributing to Zeppelin?
-
-- Framework proposal and roadmap: https://medium.com/zeppelin-blog/zeppelin-framework-proposal-and-development-roadmap-fdfa9a3a32ab#.iain47pak
-- Issue tracker: https://github.com/OpenZeppelin/zeppelin-solidity/issues
-- Contribution guidelines: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/CONTRIBUTING.md
-
-## Collaborating organizations and audits by Zeppelin
-- [Golem](https://golem.network/)
-- [Mediachain](https://golem.network/)
-- [Truffle](http://truffleframework.com/)
-- [Firstblood](http://firstblood.io/)
-- [Rootstock](http://www.rsk.co/)
-- [Consensys](https://consensys.net/)
-- [DigixGlobal](https://www.dgx.io/)
-- [Coinfund](https://coinfund.io/)
-- [DemocracyEarth](http://democracy.earth/)
-- [Signatura](https://signatura.co/)
-- [Ether.camp](http://www.ether.camp/)
-
-among others...
+## Contribute
 
+OpenZeppelin exists thanks to its contributors. There are many ways you can participate and help build high quality software. Check out the [contribution guide]!
 
 ## License
-Code released under the [MIT License](https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/LICENSE).
+
+OpenZeppelin is released under the [MIT License](LICENSE).
+
+[API docs]: https://docs.openzeppelin.org/v2.3.0/api/token/erc20
+[guides]: https://docs.openzeppelin.org/v2.3.0/get-started
+[forum]: https://forum.zeppelin.solutions
+[contribution guide]: CONTRIBUTING.md

RELEASING.md

@@ -0,0 +1,99 @@
+# Releasing
+
+This document describes our release process, and contains the steps to be followed by an OpenZeppelin maintainer at the several stages of a release.
+
+We release a new version of OpenZeppelin monthly. Release cycles are tracked in the [issue milestones](https://github.com/OpenZeppelin/openzeppelin-solidity/milestones).
+
+Each release has at least one release candidate published first, intended for community review and any critical fixes that may come out of it. At the moment we leave 1 week between the first release candidate and the final release.
+
+Before starting make sure to verify the following items.
+* Your local `master` branch is in sync with your `upstream` remote (it may have another name depending on your setup).
+* Your repo is clean, particularly with no untracked files in the contracts and tests directories. Verify with `git clean -n`.
+
+
+## Creating the release branch
+
+We'll refer to a release `vX.Y.Z`.
+
+```
+git checkout master
+git checkout -b release-vX.Y.Z
+```
+
+## Creating a release candidate
+
+Once in the release branch, change the version string in `package.json`, `package-lock.json` and `ethpm.json` to `X.Y.Z-rc.R`. (This will be `X.Y.Z-rc.1` for the first release candidate.) Commit these changes and tag the commit as `vX.Y.Z-rc.R`.
+
+```
+git add package.json package-lock.json ethpm.json
+git commit -m "Release candidate vX.Y.Z-rc.R"
+git tag -a vX.Y.Z-rc.R
+git push upstream release-vX.Y.Z
+git push upstream vX.Y.Z-rc.R
+```
+
+Draft the release notes in our [GitHub releases](https://github.com/OpenZeppelin/openzeppelin-solidity/releases). Make sure to mark it as a pre-release! Try to be consistent with our previous release notes in the title and format of the text. Release candidates don't need a detailed changelog, but make sure to include a link to GitHub's compare page.
+
+Once the CI run for the new tag is green, publish on npm under the `next` tag. You should see the contracts compile automatically.
+
+```
+npm publish --tag next
+```
+
+Publish the release notes on GitHub and ask our community manager to announce the release candidate on at least Slack and Twitter.
+
+## Creating the final release
+
+Make sure to have the latest changes from `upstream` in your local release branch.
+
+```
+git checkout release-vX.Y.Z
+git pull upstream
+```
+
+Before starting the release process, make one final commit to CHANGELOG.md, including the date of the release.
+
+Change the version string in `package.json`, `package-lock.json` and `ethpm.json` removing the "-rc.R" suffix. Commit these changes and tag the commit as `vX.Y.Z`.
+
+```
+git add package.json package-lock.json ethpm.json
+git commit -m "Release vX.Y.Z"
+git tag -a vX.Y.Z
+git push upstream release-vX.Y.Z
+git push upstream vX.Y.Z
+```
+
+Draft the release notes in GitHub releases. Try to be consistent with our previous release notes in the title and format of the text. Make sure to include a detailed changelog.
+
+Once the CI run for the new tag is green, publish on npm. You should see the contracts compile automatically.
+
+```
+npm publish
+```
+
+Publish the release notes on GitHub and ask our community manager to announce the release!
+
+Delete the `next` tag in the npm package as there is no longer a release candidate.
+
+```
+npm dist-tag rm --otp $2FA_CODE openzeppelin-solidity next
+```
+
+## Merging the release branch
+
+After the final release, the release branch should be merged back into `master`. This merge must not be squashed because it would lose the tagged release commit. Since the GitHub repo is set up to only allow squashed merges, the merge should be done locally and pushed.
+
+Make sure to have the latest changes from `upstream` in your local release branch.
+
+```
+git checkout release-vX.Y.Z
+git pull upstream
+```
+
+```
+git checkout master
+git merge --no-ff release-vX.Y.Z
+git push upstream master
+```
+
+The release branch can then be deleted on GitHub.

audit/2017-03.md

@@ -0,0 +1,290 @@
+# OpenZeppelin Audit
+
+March, 2017
+Authored by Dennis Peterson and Peter Vessenes
+
+# Introduction
+
+Zeppelin requested that New Alchemy perform an audit of the contracts in their OpenZeppelin library. The OpenZeppelin contracts are a set of contracts intended to be a safe building block for a variety of uses by parties that may not be as sophisticated as the OpenZeppelin team. It is a design goal that the contracts be deployable safely and "as-is".
+
+The contracts are hosted at:
+
+https://github.com/OpenZeppelin/zeppelin-solidity
+
+All the contracts in the "contracts" folder are in scope.
+
+The git commit hash we evaluated is:
+9c5975a706b076b7000e8179f8101e0c61024c87
+
+# Disclaimer
+
+The audit makes no statements or warrantees about utility of the code, safety of the code, suitability of the business model, regulatory regime for the business model, or any other statements about fitness of the contracts to purpose, or their bugfree status. The audit documentation is for discussion purposes only.
+
+# Executive Summary
+
+Overall the OpenZeppelin codebase is of reasonably high quality -- it is clean, modular and follows best practices throughout.
+
+It is still in flux as a codebase, and needs better documentation per file as to expected behavior and future plans. It probably needs more comprehensive and aggressive tests written by people less nice than the current OpenZeppelin team.
+
+We identified two critical errors and one moderate issue, and would not recommend this commit hash for public use until these bugs are remedied.
+
+The repository includes a set of Truffle unit tests, a requirement and best practice for smart contracts like these; we recommend these be bulked up.
+
+# Discussion
+
+## Big Picture: Is This A Worthwhile Project?
+
+As soon as a developer touches OpenZeppelin contracts, they will modify something, leaving them in an un-audited state. We do not recommend developers deploy any unaudited code to the Blockchain if it will handle money, information or other things of value.
+
+> "In accordance with Unix philosophy, Perl gives you enough rope to hang yourself"
+> --Larry Wall
+
+We think this is an incredibly worthwhile project -- aided by the high code quality. Creating a framework that can be easily extended helps increase the average code quality on the Blockchain by charting a course for developers and encouraging containment of modifications to certain sections.
+
+> "Rust: The language that makes you take the safety off before shooting yourself in the foot"
+> -- (@mbrubeck)
+
+We think much more could be done here, and recommend the OpenZeppelin team keep at this and keep focusing on the design goal of removing rope and adding safety.
+
+## Solidity Version Updates Recommended
+
+Most of the code uses Solidity 0.4.11, but some files under `Ownership` are marked 0.4.0. These should be updated.
+
+Solidity 0.4.10 will add several features which could be useful in these contracts:
+
+- `assert(condition)`, which throws if the condition is false
+
+- `revert()`, which rolls back without consuming all remaining gas.
+
+- `address.transfer(value)`, which is like `send` but automatically propagates exceptions, and supports `.gas()`. See https://github.com/ethereum/solidity/issues/610 for more on this.
+
+## Error Handling: Throw vs Return False
+Solidity standards allow two ways to handle an error -- either calling `throw` or returning `false`. Both have benefits. In particular, a `throw` guarantees a complete wipe of the call stack (up to the preceding external call), whereas `false` allows a function to continue.
+
+In general we prefer `throw` in our code audits, because it is simpler -- it's less for an engineer to keep track of. Returning `false` and using logic to check results can quickly become a poorly-tracked state machine, and this sort of complexity can cause errors.
+
+In the OpenZeppelin contracts, both styles are used in different parts of the codebase. `SimpleToken` transfers throw upon failure, while the full ERC20 token returns `false`. Some modifiers `throw`, others just wrap the function body in a conditional, effectively allowing the function to return false if the condition is not met.
+
+We don't love this, and would usually recommend you stick with one style or the other throughout the codebase.
+
+In at least one case, these different techniques are combined cleverly (see the Multisig comments, line 65). As a set of contracts intended for general use, we recommend you either strive for more consistency or document explicit design criteria that govern which techniques are used where.
+
+Note that it may be impossible to use either one in all situations. For example, SafeMath functions pretty much have to throw upon failure, but ERC20 specifies returning booleans. Therefore we make no particular recommendations, but simply point out inconsistencies to consider.
+
+# Critical Issues
+
+## Stuck Ether in Crowdsale contract
+CrowdsaleToken.sol has no provision for withdrawing the raised ether. We *strongly* recommend a standard `withdraw` function be added. There is no scenario in which someone should deploy this contract as is, whether for testing or live.
+
+## Recursive Call in MultisigWallet
+Line 45 of `MultisigWallet.sol` checks if the amount being sent by `execute` is under a daily limit.
+
+This function can only be called by the "Owner". As a first angle of attack, it's worth asking what will happen if the multisig wallet owners reset the daily limit by approving a call to `resetSpentToday`.
+
+If a chain of calls can be constructed in which the owner confirms the `resetSpentToday` function and then withdraws through `execute` in a recursive call, the contract can be drained. In fact, this could be done without a recursive call, just through repeated `execute` calls alternating with the `confirm` calls.
+
+We are still working through the confirmation protocol in `Shareable.sol`, but we are not convinced that this is impossible, in fact it looks possible. The flexibility any shared owner has in being able to revoke confirmation later is another worrisome angle of approach even if some simple patches are included.
+
+This bug has a number of causes that need to be addressed:
+
+1. `resetSpentToday` and `confirm` together do not limit the days on which the function can be called or (it appears) the number of times it can be called.
+1. Once a call has been confirmed and `execute`d it appears that it can be re-executed. This is not good.
+3. `confirmandCheck` doesn't seem to have logic about whether or not the function in question has been called.
+4. Even if it did, `revoke` would need updates and logic to deal with revocation requests after a function call had been completed.
+
+We do not recommend using the MultisigWallet until these issues are fixed.
+
+# Moderate to Minor Issues
+
+## PullPayment
+PullPayment.sol needs some work. It has no explicit provision for cancelling a payment. This would be desirable in a number of scenarios; consider a payee losing their wallet, or giving a griefing address, or just an address that requires more than the default gas offered by `send`.
+
+`asyncSend` has no overflow checking. This is a bad plan. We recommend overflow and underflow checking at the layer closest to the data manipulation.
+
+`asyncSend` allows more balance to be queued up for sending than the contract holds. This is probably a bad idea, or at the very least should be called something different. If the intent is to allow this, it should have provisions for dealing with race conditions between competing `withdrawPayments` calls.
+
+It would be nice to see how many payments are pending. This would imply a bit of a rewrite; we recommend this contract get some design time, and that developers don't rely on it in its current state.
+
+## Shareable Contract
+
+We do not believe the `Shareable.sol` contract is ready for primetime. It is missing functions, and as written may be vulnerable to a reordering attack -- an attack in which a miner or other party "racing" with a smart contract participant inserts their own information into a list or mapping.
+
+The confirmation and revocation code needs to be looked over with a very careful eye imagining extraordinarily bad behavior by shared owners before this contract can be called safe.
+
+No sanity checks on the initial constructor's `required` argument are worrisome as well.
+
+# Line by Line Comments
+
+## Lifecycle
+
+### Killable
+
+Very simple, allows owner to call selfdestruct, sending funds to owner. No issues. However, note that `selfdestruct` should typically not be used; it is common that a developer may want to access data in a former contract, and they may not understand that `selfdestruct` limits access to the contract. We recommend better documentation about this dynamic, and an alternate function name for `kill` like `completelyDestroy` while `kill` would perhaps merely send funds to the owner.
+
+Also note that a killable function allows the owner to take funds regardless of other logic. This may be desirable or undesirable depending on the circumstances. Perhaps `Killable` should have a different name as well.
+
+### Migrations
+
+I presume that the goal of this contract is to allow and annotate a migration to a new smart contract address. We are not clear here how this would be accomplished by the code; we'd like to review with the OpenZeppelin team.
+
+### Pausable
+
+We like these pauses! Note that these allow significant griefing potential by owners, and that this might not be obvious to participants in smart contracts using the OpenZeppelin framework. We would recommend that additional sample logic be added to for instance the TokenContract showing safer use of the pause and resume functions. In particular, we would recommend a timelock after which anyone could unpause the contract.
+
+The modifers use the pattern `if(bool){_;}`. This is fine for functions that return false upon failure, but could be problematic for functions expected to throw upon failure. See our comments above on standardizing on `throw` or `return(false)`.
+
+## Ownership
+
+### Ownable
+
+Line 19: Modifier throws if doesn't meet condition, in contrast to some other inheritable modifiers (e.g. in Pausable) that use `if(bool){_;}`.
+
+### Claimable
+
+Inherits from Ownable but the existing owner sets a pendingOwner who has to claim ownership.
+
+Line 17: Another modifier that throws.
+
+### DelayedClaimable
+
+Is there any reason to descend from Ownable directly, instead of just Claimable, which descends from Ownable? If not, descending from both just adds confusion.
+
+### Contactable
+
+Allows owner to set a public string of contract information. No issues.
+
+### Shareable
+
+This needs some work. Doesn't check if `_required <= len(_owners)` for instance, that would be a bummer. What if _required were like `MAX - 1`?
+
+I have a general concern about the difference between `owners`, `_owners`, and `owner` in `Ownable.sol`. I recommend "Owners" be renamed. In general we do not recomment single character differences in variable names, although a preceding underscore is not uncommon in Solidity code.
+
+Line 34: "this contract only has six types of events"...actually only two.
+
+Line 61: Why is `ownerIndex` keyed by addresses hashed to `uint`s? Why not use the addresses directly, so `ownerIndex` is less obscure, and so there's stronger typing?
+
+Line 62: Do not love `++i) ... owners[2+ i]`. Makes me do math, which is not what I want to do. I want to not have to do math.
+
+There should probably be a function for adding a new operation, so the developer doesn't have to work directly with the internal data. (This would make the multisig contract even shorter.)
+
+There's a `revoke` function but not a `propose` function that we can see.
+
+Beware reordering. If `propose` allows the user to choose a bytes string for their proposal, bad things(TM) will happen as currently written.
+
+
+### Multisig
+
+Just an interface. Note it allows changing an owner address, but not changing the number of owners. This is somewhat limiting but also simplifies implementation.
+
+## Payment
+
+### PullPayment
+
+Safe from reentrance attack since ether send is at the end, plus it uses `.send()` rather than `.call.value()`.
+
+There's an argument to be made that `.call.value()` is a better option *if* you're sure that it will be done after all state updates, since `.send` will fail if the recipient has an expensive fallback function. However, in the context of a function meant to be embedded in other contracts, it's probably better to use `.send`. One possible compromise is to add a function which allows only the owner to send ether via `.call.value`.
+
+If you don't use `call.value` you should implement a `cancel` function in case some value is pending here.
+
+Line 14:
+Doesn't use safeAdd. Although it appears that payout amounts can only be increased, in fact the payer could lower the payout as much as desired via overflow. Also, the payer could add a large non-overflowing amount, causing the payment to exceed the contract balance and therefore fail when withdraw is attempted.
+
+Recommendation: track the sum of non-withdrawn asyncSends, and don't allow a new one which exceeds the leftover balance. If it's ever desirable to make payments revocable, it should be done explicitly.
+
+## Tokens
+
+### ERC20
+
+Standard ERC20 interface only.
+
+There's a security hole in the standard, reported at Edcon: `approve` does not protect against race conditions and simply replaces the current value. An approved spender could wait for the owner to call `approve` again, then attempt to spend the old limit before the new limit is applied. If successful, this attacker could successfully spend the sum of both limits.
+
+This could be fixed by either (1) including the old limit as a parameter, so the update will fail if some gets spent, or (2) using the value parameter as a delta instead of replacement value.
+
+This is not fixable while adhering to the current full ERC20 standard, though it would be possible to add a "secureApprove" function. The impact isn't extreme since at least you can only be attacked by addresses you approved. Also, users could mitigate this by always setting spending limits to zero and checking for spends, before setting the new limit.
+
+Edcon slides:
+https://drive.google.com/file/d/0ByMtMw2hul0EN3NCaVFHSFdxRzA/view
+
+### ERC20Basic
+
+Simpler interface skipping the Approve function. Note this departs from ERC20 in another way: transfer throws instead of returning false.
+
+### BasicToken
+
+Uses `SafeSub` and `SafeMath`, so transfer `throw`s instead of returning false. This complies with ERC20Basic but not the actual ERC20 standard.
+
+### StandardToken
+
+Implementation of full ERC20 token.
+
+Transfer() and transferFrom() use SafeMath functions, which will cause them to throw instead of returning false. Not a security issue but departs from standard.
+
+### SimpleToken
+
+Sample instantiation of StandardToken. Note that in this sample, decimals is 18 and supply only 10,000, so the supply is a small fraction of a single nominal token.
+
+### CrowdsaleToken
+
+StandardToken which mints tokens at a fixed price when sent ether.
+
+There's no provision for owner withdrawing the ether. As a sample for crowdsales it should be Ownable and allow the owner to withdraw ether, rather than stranding the ether in the contract.
+
+Note: an alternative pattern is a mint() function which is only callable from a separate crowdsale contract, so any sort of rules can be added without modifying the token itself.
+
+### VestedToken
+
+Lines 23, 27:
+Functions `transfer()` and `transferFrom()` have a modifier canTransfer which throws if not enough tokens are available. However, transfer() returns a boolean success. Inconsistent treatment of failure conditions may cause problems for other contracts using the token. (Note that transferableTokens() relies on safeSub(), so will also throw if there's insufficient balance.)
+
+Line 64:
+Delete not actually necessary since the value is overwritten in the next line anyway.
+
+## Root level
+
+### Bounty
+
+Avoids potential race condition by having each researcher deploy a separate contract for attack; if a research manages to break his associated contract, other researchers can't immediately claim the reward, they have to reproduce the attack in their own contracts.
+
+A developer could subvert this intent by implementing `deployContract()` to always return the same address. However, this would break the `researchers` mapping, updating the researcher address associated with the contract. This could be prevented by blocking rewrites in `researchers`.
+
+### DayLimit
+
+The modifier `limitedDaily` calls `underLimit`, which both checks that the spend is below the daily limit, and adds the input value to the daily spend. This is fine if all functions throw upon failure. However, not all OpenZeppelin functions do this; there are functions that returns false, and modifiers that wrap the function body in `if (bool) {_;}`. In these cases, `_value` will be added to `spentToday`, but ether may not actually be sent because other preconditions were not met. (However in the OpenZeppelin multisig this is not a problem.)
+
+Lines 4, 11:
+Comment claims that `DayLimit` is multiowned, and Shareable is imported, but DayLimit does not actually inherit from Shareable. The intent may be for child contracts to inherit from Shareable (as Multisig does); in this case the import should be removed and the comment altered.
+
+Line 46:
+Manual overflow check instead of using safeAdd. Since this is called from a function that throws upon failure anyway, there's no real downside to using safeAdd.
+
+### LimitBalance
+
+No issues.
+
+### MultisigWallet
+
+Lines 28, 76, 80:
+`kill`, `setDailyLimit`, and `resetSpentToday` only happen with multisig approval, and hashes for these actions are logged by Shareable. However, they should probably post their own events for easy reading.
+
+Line 45:
+This call to underLimit will reduce the daily limit, and then either throw or return 0. So in this case there's no danger that the limit will be reduced without the operation going through.
+
+Line 65:
+Shareable's onlyManyOwners will take the user's confirmation, and execute the function body if and only if enough users have confirmed. Whole thing throws if the send fails, which will roll back the confirmation. Confirm returns false if not enough have confirmed yet, true if the whole thing succeeds, and throws only in the exceptional circumstance that the designated transaction unexpectedly fails. Elegant design.
+
+Line 68:
+Throw here is good but note this function can fail either by returning false or by throwing.
+
+Line 92:
+A bit odd to split `clearPending()` between this contract and Shareable. However this does allow contracts inheriting from Shareable to use custom structs for pending transactions.
+
+
+### SafeMath
+
+Another interesting comment from the same Edcon presentation was that the overflow behavior of Solidity is undocumented, so in theory, source code that relies on it could break with a future revision.
+
+However, compiled code should be fine, and in the unlikely event that the compiler is revised in this way, there should be plenty of warning. (But this is an argument for keeping overflow checks isolated in SafeMath.)
+
+Aside from that small caveat, these are fine.
+

contracts/.npmignore

@@ -0,0 +1,2 @@
+mocks
+examples

contracts/ARCHITECTURE.md

@@ -0,0 +1,27 @@
+## Architecture
+
+The following provides visibility into how OpenZeppelin's contracts are organized:
+
+- **access** - Smart contracts that enable functionality that can be used for selective restrictions and basic authorization control functions.
+- **crowdsale** - A collection of smart contracts used to manage token crowdsales that allow investors to purchase tokens with ETH. Includes a base contract which implements fundamental crowdsale functionality in its simplest form. The base contract can be extended in order to satisfy your crowdsale’s specific requirements.
+	- **distribution** - Includes extensions of the base crowdsale contract which can be used to customize the completion of a crowdsale.
+	- **emission** - Includes extensions of the base crowdsale contract which can be used to mint and manage how tokens are issued to purchasers.
+	- **price** - Includes extensions of the crowdsale contract that can be used to manage changes in token prices.
+	- **validation**  - Includes extensions of the crowdsale contract that can be used to enforce restraints and limit access to token purchases.
+- **examples** - A collection of simple smart contracts that demonstrate how to add new features to base contracts through multiple inheritance.
+- **introspection**  - An interface that can be used to make a contract comply with the ERC-165 standard as well as a contract that implements ERC-165 using a lookup table.
+- **lifecycle** - A collection of base contracts used to manage the existence and behavior of your contracts and their funds.
+- **math** - Libraries with safety checks on operations that throw on errors.
+- **mocks** - A collection of abstract contracts that are primarily used for unit testing. They also serve as good usage examples and demonstrate how to combine contracts with inheritance when developing your own custom applications.
+- **ownership** - A collection of smart contracts that can be used to manage contract and token ownership
+- **payment** - A collection of smart contracts that can be used to manage payments through escrow arrangements, withdrawals, and claims. Includes support for both single payees and multiple payees.
+- **proposals** - A collection of smart contracts that reflect community Ethereum Improvement Proposals (EIPs). These contracts are under development and standardization. They are not recommended for production, but they are useful for experimentation with pending EIP standards. Go [here](https://github.com/OpenZeppelin/openzeppelin-solidity/wiki/ERC-Process) for more information.
+
+- **token** - A collection of approved ERC standard tokens -- their interfaces and implementations.
+	- **ERC20** - A standard interface for fungible tokens:
+		- *Interfaces* - Includes the ERC-20 token standard basic interface. I.e., what the contract’s ABI can represent.
+		- *Implementations* - Includes ERC-20 token implementations that include all required and some optional ERC-20 functionality.
+	- **ERC721** - A standard interface for non-fungible tokens
+		- *Interfaces* - Includes the ERC-721 token standard basic interface. I.e., what the contract’s ABI can represent.
+		- *Implementations* - Includes ERC-721 token implementations that include all required and some optional ERC-721 functionality.
+

contracts/Bounty.sol

@@ -1,58 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import './PullPayment.sol';
-import './Killable.sol';
-
-
-/*
- * Bounty
- * 
- * This bounty will pay out to a researcher if they break invariant logic of the contract.
- */
-contract Bounty is PullPayment, Killable {
-  Target target;
-  bool public claimed;
-  mapping(address => address) public researchers;
-
-  event TargetCreated(address createdAddress);
-
-  function() payable {
-    if (claimed) throw;
-  }
-
-  function createTarget() returns(Target) {
-    target = Target(deployContract());
-    researchers[target] = msg.sender;
-    TargetCreated(target);
-    return target;
-  }
-
-  function deployContract() internal returns(address);
-
-  function checkInvariant() returns(bool){
-    return target.checkInvariant();
-  }
-
-  function claim(Target target) {
-    address researcher = researchers[target];
-    if (researcher == 0) throw;
-    // Check Target contract invariants
-    if (target.checkInvariant()) {
-      throw;
-    }
-    asyncSend(researcher, this.balance);
-    claimed = true;
-  }
-
-}
-
-/*
- * Target
- * 
- * Your main contract should inherit from this class and implement the checkInvariant method. This is a function that should check everything your contract assumes to be true all the time. If this function returns false, it means your contract was broken in some way and is in an inconsistent state. This is what security researchers will try to acomplish when trying to get the bounty.
- */
-contract Target {
-  function checkInvariant() returns(bool);
-}
-

contracts/Claimable.sol

@@ -1,29 +0,0 @@
-pragma solidity ^0.4.0;
-
-
-import './Ownable.sol';
-
-
-/*
- * Claimable
- *
- * Extension for the Ownable contract, where the ownership needs to be claimed. This allows the new owner to accept the transfer.
- */
-contract Claimable is Ownable {
-  address public pendingOwner;
-
-  modifier onlyPendingOwner() {
-    if (msg.sender == pendingOwner)
-      _;
-  }
-
-  function transferOwnership(address newOwner) onlyOwner {
-    pendingOwner = newOwner;
-  }
-
-  function claimOwnership() onlyPendingOwner {
-    owner = pendingOwner;
-    pendingOwner = 0x0;
-  }
-
-}

contracts/DayLimit.sol

@@ -1,75 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import './Shareable.sol';
-
-
-/*
- * DayLimit
- *
- * inheritable "property" contract that enables methods to be protected by placing a linear limit (specifiable)
- * on a particular resource per calendar day. is multiowned to allow the limit to be altered. resource that method
- * uses is specified in the modifier.
- */
-contract DayLimit {
-  // FIELDS
-
-  uint public dailyLimit;
-  uint public spentToday;
-  uint public lastDay;
-
-
-  // MODIFIERS
-
-  // simple modifier for daily limit.
-  modifier limitedDaily(uint _value) {
-    if (underLimit(_value))
-      _;
-  }
-
-
-  // CONSTRUCTOR
-  // stores initial daily limit and records the present day's index.
-  function DayLimit(uint _limit) {
-    dailyLimit = _limit;
-    lastDay = today();
-  }
-
-
-  // METHODS
-
-  // (re)sets the daily limit. doesn't alter the amount already spent today.
-  function _setDailyLimit(uint _newLimit) internal {
-    dailyLimit = _newLimit;
-  }
-
-  // resets the amount already spent today.
-  function _resetSpentToday() internal {
-    spentToday = 0;
-  }
-
-
-  // INTERNAL METHODS
-
-  // checks to see if there is at least `_value` left from the daily limit today. if there is, subtracts it and
-  // returns true. otherwise just returns false.
-  function underLimit(uint _value) internal returns (bool) {
-    // reset the spend limit if we're on a different day to last time.
-    if (today() > lastDay) {
-      spentToday = 0;
-      lastDay = today();
-    }
-    // check to see if there's enough left - if so, subtract and return true.
-    // overflow protection                    // dailyLimit check
-    if (spentToday + _value >= spentToday && spentToday + _value <= dailyLimit) {
-      spentToday += _value;
-      return true;
-    }
-    return false;
-  }
-
-  // determines today's index.
-  function today() private constant returns (uint) {
-    return now / 1 days;
-  }
-}

contracts/DelayedClaimable.sol

@@ -1,30 +0,0 @@
-pragma solidity ^0.4.4;
-import './Ownable.sol';
-import './Claimable.sol';
-
-/*
- * DelayedClaimable
- * Extension for the Claimable contract, where the ownership needs to be claimed before/after certain block number
- */
-
-contract DelayedClaimable is Ownable, Claimable {
-
-  uint public claimBeforeBlock;
-  uint public claimAfterBlock;
-
-  function setClaimBlocks(uint _claimBeforeBlock, uint _claimAfterBlock) onlyOwner {
-    if (_claimAfterBlock > claimBeforeBlock)
-        throw;
-    claimBeforeBlock = _claimBeforeBlock;
-    claimAfterBlock = _claimAfterBlock;
-  }
-
-  function claimOwnership() onlyPendingOwner {
-    if ((block.number > claimBeforeBlock) || (block.number < claimAfterBlock))
-        throw;
-    owner = pendingOwner;
-    pendingOwner = 0x0;
-    claimBeforeBlock = 0;
-  }
-
-}

contracts/GSN/Context.sol

@@ -0,0 +1,27 @@
+pragma solidity ^0.5.0;
+
+/*
+ * @dev Provides information about the current execution context, including the
+ * sender of the transaction and its data. While these are generally available
+ * via msg.sender and msg.data, they not should not be accessed in such a direct
+ * manner, since when dealing with GSN meta-transactions the account sending and
+ * paying for execution may not be the actual sender (as far as an application
+ * is concerned).
+ *
+ * This contract is only required for intermediate, library-like contracts.
+ */
+contract Context {
+    // Empty internal constructor, to prevent people from mistakenly deploying
+    // an instance of this contract, with should be used via inheritance.
+    constructor () internal { }
+    // solhint-disable-previous-line no-empty-blocks
+
+    function _msgSender() internal view returns (address) {
+        return msg.sender;
+    }
+
+    function _msgData() internal view returns (bytes memory) {
+        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
+        return msg.data;
+    }
+}

contracts/GSN/GSNContext.sol

@@ -0,0 +1,103 @@
+pragma solidity ^0.5.0;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "./Context.sol";
+
+/*
+ * @dev Enables GSN support on `Context` contracts by recognizing calls from
+ * RelayHub and extracting the actual sender and call data from the received
+ * calldata.
+ *
+ * > This contract does not perform all required tasks to implement a GSN
+ * recipient contract: end users should use `GSNRecipient` instead.
+ */
+contract GSNContext is Initializable, Context {
+    // We use a random storage slot to allow proxy contracts to enable GSN support in an upgrade without changing their
+    // storage layout. This value is calculated as: keccak256('gsn.relayhub.address'), minus 1.
+    bytes32 private constant RELAY_HUB_ADDRESS_STORAGE_SLOT = 0x06b7792c761dcc05af1761f0315ce8b01ac39c16cc934eb0b2f7a8e71414f262;
+
+    event RelayHubChanged(address indexed oldRelayHub, address indexed newRelayHub);
+
+    function initialize() public initializer {
+        _upgradeRelayHub(0xD216153c06E857cD7f72665E0aF1d7D82172F494);
+    }
+
+    function _getRelayHub() internal view returns (address relayHub) {
+        bytes32 slot = RELAY_HUB_ADDRESS_STORAGE_SLOT;
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            relayHub := sload(slot)
+        }
+    }
+
+    function _upgradeRelayHub(address newRelayHub) internal {
+        address currentRelayHub = _getRelayHub();
+        require(newRelayHub != address(0), "GSNContext: new RelayHub is the zero address");
+        require(newRelayHub != currentRelayHub, "GSNContext: new RelayHub is the current one");
+
+        emit RelayHubChanged(currentRelayHub, newRelayHub);
+
+        bytes32 slot = RELAY_HUB_ADDRESS_STORAGE_SLOT;
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            sstore(slot, newRelayHub)
+        }
+    }
+
+    // Overrides for Context's functions: when called from RelayHub, sender and
+    // data require some pre-processing: the actual sender is stored at the end
+    // of the call data, which in turns means it needs to be removed from it
+    // when handling said data.
+
+    function _msgSender() internal view returns (address) {
+        if (msg.sender != _getRelayHub()) {
+            return msg.sender;
+        } else {
+            return _getRelayedCallSender();
+        }
+    }
+
+    function _msgData() internal view returns (bytes memory) {
+        if (msg.sender != _getRelayHub()) {
+            return msg.data;
+        } else {
+            return _getRelayedCallData();
+        }
+    }
+
+    function _getRelayedCallSender() private pure returns (address result) {
+        // We need to read 20 bytes (an address) located at array index msg.data.length - 20. In memory, the array
+        // is prefixed with a 32-byte length value, so we first add 32 to get the memory read index. However, doing
+        // so would leave the address in the upper 20 bytes of the 32-byte word, which is inconvenient and would
+        // require bit shifting. We therefore subtract 12 from the read index so the address lands on the lower 20
+        // bytes. This can always be done due to the 32-byte prefix.
+
+        // The final memory read index is msg.data.length - 20 + 32 - 12 = msg.data.length. Using inline assembly is the
+        // easiest/most-efficient way to perform this operation.
+
+        // These fields are not accessible from assembly
+        bytes memory array = msg.data;
+        uint256 index = msg.data.length;
+
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those.
+            result := and(mload(add(array, index)), 0xffffffffffffffffffffffffffffffffffffffff)
+        }
+        return result;
+    }
+
+    function _getRelayedCallData() private pure returns (bytes memory) {
+        // RelayHub appends the sender address at the end of the calldata, so in order to retrieve the actual msg.data,
+        // we must strip the last 20 bytes (length of an address type) from it.
+
+        uint256 actualDataLength = msg.data.length - 20;
+        bytes memory actualData = new bytes(actualDataLength);
+
+        for (uint256 i = 0; i < actualDataLength; ++i) {
+            actualData[i] = msg.data[i];
+        }
+
+        return actualData;
+    }
+}

contracts/GSN/GSNRecipient.sol

@@ -0,0 +1,33 @@
+pragma solidity ^0.5.0;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "./IRelayRecipient.sol";
+import "./GSNContext.sol";
+import "./bouncers/GSNBouncerBase.sol";
+import "./IRelayHub.sol";
+
+/*
+ * @dev Base GSN recipient contract, adding the recipient interface and enabling
+ * GSN support. Not all interface methods are implemented, derived contracts
+ * must do so themselves.
+ */
+contract GSNRecipient is Initializable, IRelayRecipient, GSNContext, GSNBouncerBase {
+    function initialize() public initializer {
+        GSNContext.initialize();
+    }
+
+    function getHubAddr() public view returns (address) {
+        return _getRelayHub();
+    }
+
+    // This function is view for future-proofing, it may require reading from
+    // storage in the future.
+    function relayHubVersion() public view returns (string memory) {
+        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
+        return "1.0.0";
+    }
+
+    function _withdrawDeposits(uint256 amount, address payable payee) internal {
+        IRelayHub(_getRelayHub()).withdraw(amount, payee);
+    }
+}

contracts/GSN/IRelayHub.sol

@@ -0,0 +1,188 @@
+pragma solidity ^0.5.0;
+
+contract IRelayHub {
+    // Relay management
+
+    // Add stake to a relay and sets its unstakeDelay.
+    // If the relay does not exist, it is created, and the caller
+    // of this function becomes its owner. If the relay already exists, only the owner can call this function. A relay
+    // cannot be its own owner.
+    // All Ether in this function call will be added to the relay's stake.
+    // Its unstake delay will be assigned to unstakeDelay, but the new value must be greater or equal to the current one.
+    // Emits a Staked event.
+    function stake(address relayaddr, uint256 unstakeDelay) external payable;
+
+    // Emited when a relay's stake or unstakeDelay are increased
+    event Staked(address indexed relay, uint256 stake, uint256 unstakeDelay);
+
+    // Registers the caller as a relay.
+    // The relay must be staked for, and not be a contract (i.e. this function must be called directly from an EOA).
+    // Emits a RelayAdded event.
+    // This function can be called multiple times, emitting new RelayAdded events. Note that the received transactionFee
+    // is not enforced by relayCall.
+    function registerRelay(uint256 transactionFee, string memory url) public;
+
+    // Emitted when a relay is registered or re-registerd. Looking at these events (and filtering out RelayRemoved
+    // events) lets a client discover the list of available relays.
+    event RelayAdded(address indexed relay, address indexed owner, uint256 transactionFee, uint256 stake, uint256 unstakeDelay, string url);
+
+    // Removes (deregisters) a relay. Unregistered (but staked for) relays can also be removed. Can only be called by
+    // the owner of the relay. After the relay's unstakeDelay has elapsed, unstake will be callable.
+    // Emits a RelayRemoved event.
+    function removeRelayByOwner(address relay) public;
+
+    // Emitted when a relay is removed (deregistered). unstakeTime is the time when unstake will be callable.
+    event RelayRemoved(address indexed relay, uint256 unstakeTime);
+
+    // Deletes the relay from the system, and gives back its stake to the owner. Can only be called by the relay owner,
+    // after unstakeDelay has elapsed since removeRelayByOwner was called.
+    // Emits an Unstaked event.
+    function unstake(address relay) public;
+
+    // Emitted when a relay is unstaked for, including the returned stake.
+    event Unstaked(address indexed relay, uint256 stake);
+
+    // States a relay can be in
+    enum RelayState {
+        Unknown, // The relay is unknown to the system: it has never been staked for
+        Staked, // The relay has been staked for, but it is not yet active
+        Registered, // The relay has registered itself, and is active (can relay calls)
+        Removed    // The relay has been removed by its owner and can no longer relay calls. It must wait for its unstakeDelay to elapse before it can unstake
+    }
+
+    // Returns a relay's status. Note that relays can be deleted when unstaked or penalized.
+    function getRelay(address relay) external view returns (uint256 totalStake, uint256 unstakeDelay, uint256 unstakeTime, address payable owner, RelayState state);
+
+    // Balance management
+
+    // Deposits ether for a contract, so that it can receive (and pay for) relayed transactions. Unused balance can only
+    // be withdrawn by the contract itself, by callingn withdraw.
+    // Emits a Deposited event.
+    function depositFor(address target) public payable;
+
+    // Emitted when depositFor is called, including the amount and account that was funded.
+    event Deposited(address indexed recipient, address indexed from, uint256 amount);
+
+    // Returns an account's deposits. These can be either a contnract's funds, or a relay owner's revenue.
+    function balanceOf(address target) external view returns (uint256);
+
+    // Withdraws from an account's balance, sending it back to it. Relay owners call this to retrieve their revenue, and
+    // contracts can also use it to reduce their funding.
+    // Emits a Withdrawn event.
+    function withdraw(uint256 amount, address payable dest) public;
+
+    // Emitted when an account withdraws funds from RelayHub.
+    event Withdrawn(address indexed account, address indexed dest, uint256 amount);
+
+    // Relaying
+
+    // Check if the RelayHub will accept a relayed operation. Multiple things must be true for this to happen:
+    //  - all arguments must be signed for by the sender (from)
+    //  - the sender's nonce must be the current one
+    //  - the recipient must accept this transaction (via acceptRelayedCall)
+    // Returns a PreconditionCheck value (OK when the transaction can be relayed), or a recipient-specific error code if
+    // it returns one in acceptRelayedCall.
+    function canRelay(
+        address relay,
+        address from,
+        address to,
+        bytes memory encodedFunction,
+        uint256 transactionFee,
+        uint256 gasPrice,
+        uint256 gasLimit,
+        uint256 nonce,
+        bytes memory signature,
+        bytes memory approvalData
+    ) public view returns (uint256 status, bytes memory recipientContext);
+
+    // Preconditions for relaying, checked by canRelay and returned as the corresponding numeric values.
+    enum PreconditionCheck {
+        OK,                         // All checks passed, the call can be relayed
+        WrongSignature,             // The transaction to relay is not signed by requested sender
+        WrongNonce,                 // The provided nonce has already been used by the sender
+        AcceptRelayedCallReverted,  // The recipient rejected this call via acceptRelayedCall
+        InvalidRecipientStatusCode  // The recipient returned an invalid (reserved) status code
+    }
+
+    // Relays a transaction. For this to suceed, multiple conditions must be met:
+    //  - canRelay must return PreconditionCheck.OK
+    //  - the sender must be a registered relay
+    //  - the transaction's gas price must be larger or equal to the one that was requested by the sender
+    //  - the transaction must have enough gas to not run out of gas if all internal transactions (calls to the
+    // recipient) use all gas available to them
+    //  - the recipient must have enough balance to pay the relay for the worst-case scenario (i.e. when all gas is
+    // spent)
+    //
+    // If all conditions are met, the call will be relayed and the recipient charged. preRelayedCall, the encoded
+    // function and postRelayedCall will be called in order.
+    //
+    // Arguments:
+    //  - from: the client originating the request
+    //  - recipient: the target IRelayRecipient contract
+    //  - encodedFunction: the function call to relay, including data
+    //  - transactionFee: fee (%) the relay takes over actual gas cost
+    //  - gasPrice: gas price the client is willing to pay
+    //  - gasLimit: gas to forward when calling the encoded function
+    //  - nonce: client's nonce
+    //  - signature: client's signature over all previous params, plus the relay and RelayHub addresses
+    //  - approvalData: dapp-specific data forwared to acceptRelayedCall. This value is *not* verified by the Hub, but
+    //    it still can be used for e.g. a signature.
+    //
+    // Emits a TransactionRelayed event.
+    function relayCall(
+        address from,
+        address to,
+        bytes memory encodedFunction,
+        uint256 transactionFee,
+        uint256 gasPrice,
+        uint256 gasLimit,
+        uint256 nonce,
+        bytes memory signature,
+        bytes memory approvalData
+    ) public;
+
+    // Emitted when an attempt to relay a call failed. This can happen due to incorrect relayCall arguments, or the
+    // recipient not accepting the relayed call. The actual relayed call was not executed, and the recipient not charged.
+    // The reason field contains an error code: values 1-10 correspond to PreconditionCheck entries, and values over 10
+    // are custom recipient error codes returned from acceptRelayedCall.
+    event CanRelayFailed(address indexed relay, address indexed from, address indexed to, bytes4 selector, uint256 reason);
+
+    // Emitted when a transaction is relayed. Note that the actual encoded function might be reverted: this will be
+    // indicated in the status field.
+    // Useful when monitoring a relay's operation and relayed calls to a contract.
+    // Charge is the ether value deducted from the recipient's balance, paid to the relay's owner.
+    event TransactionRelayed(address indexed relay, address indexed from, address indexed to, bytes4 selector, RelayCallStatus status, uint256 charge);
+
+    // Reason error codes for the TransactionRelayed event
+    enum RelayCallStatus {
+        OK,                      // The transaction was successfully relayed and execution successful - never included in the event
+        RelayedCallFailed,       // The transaction was relayed, but the relayed call failed
+        PreRelayedFailed,        // The transaction was not relayed due to preRelatedCall reverting
+        PostRelayedFailed,       // The transaction was relayed and reverted due to postRelatedCall reverting
+        RecipientBalanceChanged  // The transaction was relayed and reverted due to the recipient's balance changing
+    }
+
+    // Returns how much gas should be forwarded to a call to relayCall, in order to relay a transaction that will spend
+    // up to relayedCallStipend gas.
+    function requiredGas(uint256 relayedCallStipend) public view returns (uint256);
+
+    // Returns the maximum recipient charge, given the amount of gas forwarded, gas price and relay fee.
+    function maxPossibleCharge(uint256 relayedCallStipend, uint256 gasPrice, uint256 transactionFee) public view returns (uint256);
+
+    // Relay penalization. Any account can penalize relays, removing them from the system immediately, and rewarding the
+    // reporter with half of the relay's stake. The other half is burned so that, even if the relay penalizes itself, it
+    // still loses half of its stake.
+
+    // Penalize a relay that signed two transactions using the same nonce (making only the first one valid) and
+    // different data (gas price, gas limit, etc. may be different). The (unsigned) transaction data and signature for
+    // both transactions must be provided.
+    function penalizeRepeatedNonce(bytes memory unsignedTx1, bytes memory signature1, bytes memory unsignedTx2, bytes memory signature2) public;
+
+    // Penalize a relay that sent a transaction that didn't target RelayHub's registerRelay or relayCall.
+    function penalizeIllegalTransaction(bytes memory unsignedTx, bytes memory signature) public;
+
+    event Penalized(address indexed relay, address sender, uint256 amount);
+
+    function getNonce(address from) external view returns (uint256);
+}
+

contracts/GSN/IRelayRecipient.sol

@@ -0,0 +1,30 @@
+pragma solidity ^0.5.0;
+
+/*
+ * @dev Interface for a contract that will be called via the GSN from RelayHub.
+ */
+contract IRelayRecipient {
+    /**
+     * @dev Returns the address of the RelayHub instance this recipient interacts with.
+     */
+    function getHubAddr() public view returns (address);
+
+    function acceptRelayedCall(
+        address relay,
+        address from,
+        bytes calldata encodedFunction,
+        uint256 transactionFee,
+        uint256 gasPrice,
+        uint256 gasLimit,
+        uint256 nonce,
+        bytes calldata approvalData,
+        uint256 maxPossibleCharge
+    )
+        external
+        view
+        returns (uint256, bytes memory);
+
+    function preRelayedCall(bytes calldata context) external returns (bytes32);
+
+    function postRelayedCall(bytes calldata context, bool success, uint actualCharge, bytes32 preRetVal) external;
+}

contracts/GSN/bouncers/GSNBouncerBase.sol

@@ -0,0 +1,92 @@
+pragma solidity ^0.5.0;
+
+import "../IRelayRecipient.sol";
+
+/*
+ * @dev Base contract used to implement GSNBouncers.
+ *
+ * > This contract does not perform all required tasks to implement a GSN
+ * recipient contract: end users should use `GSNRecipient` instead.
+ */
+contract GSNBouncerBase is IRelayRecipient {
+    uint256 constant private RELAYED_CALL_ACCEPTED = 0;
+    uint256 constant private RELAYED_CALL_REJECTED = 11;
+
+    // How much gas is forwarded to postRelayedCall
+    uint256 constant internal POST_RELAYED_CALL_MAX_GAS = 100000;
+
+    // Base implementations for pre and post relayedCall: only RelayHub can invoke them, and data is forwarded to the
+    // internal hook.
+
+    /**
+     * @dev See `IRelayRecipient.preRelayedCall`.
+     *
+     * This function should not be overriden directly, use `_preRelayedCall` instead.
+     *
+     * * Requirements:
+     *
+     * - the caller must be the `RelayHub` contract.
+     */
+    function preRelayedCall(bytes calldata context) external returns (bytes32) {
+        require(msg.sender == getHubAddr(), "GSNBouncerBase: caller is not RelayHub");
+        return _preRelayedCall(context);
+    }
+
+    /**
+     * @dev See `IRelayRecipient.postRelayedCall`.
+     *
+     * This function should not be overriden directly, use `_postRelayedCall` instead.
+     *
+     * * Requirements:
+     *
+     * - the caller must be the `RelayHub` contract.
+     */
+    function postRelayedCall(bytes calldata context, bool success, uint256 actualCharge, bytes32 preRetVal) external {
+        require(msg.sender == getHubAddr(), "GSNBouncerBase: caller is not RelayHub");
+        _postRelayedCall(context, success, actualCharge, preRetVal);
+    }
+
+    /**
+     * @dev Return this in acceptRelayedCall to proceed with the execution of a relayed call. Note that this contract
+     * will be charged a fee by RelayHub
+     */
+    function _approveRelayedCall() internal pure returns (uint256, bytes memory) {
+        return _approveRelayedCall("");
+    }
+
+    /**
+     * @dev See `GSNBouncerBase._approveRelayedCall`.
+     *
+     * This overload forwards `context` to _preRelayedCall and _postRelayedCall.
+     */
+    function _approveRelayedCall(bytes memory context) internal pure returns (uint256, bytes memory) {
+        return (RELAYED_CALL_ACCEPTED, context);
+    }
+
+    /**
+     * @dev Return this in acceptRelayedCall to impede execution of a relayed call. No fees will be charged.
+     */
+    function _rejectRelayedCall(uint256 errorCode) internal pure returns (uint256, bytes memory) {
+        return (RELAYED_CALL_REJECTED + errorCode, "");
+    }
+
+    // Empty hooks for pre and post relayed call: users only have to define these if they actually use them.
+
+    function _preRelayedCall(bytes memory) internal returns (bytes32) {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    function _postRelayedCall(bytes memory, bool, uint256, bytes32) internal {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    /*
+     * @dev Calculates how much RelaHub will charge a recipient for using `gas` at a `gasPrice`, given a relayer's
+     * `serviceFee`.
+     */
+    function _computeCharge(uint256 gas, uint256 gasPrice, uint256 serviceFee) internal pure returns (uint256) {
+        // The fee is expressed as a percentage. E.g. a value of 40 stands for a 40% fee, so the recipient will be
+        // charged for 1.4 times the spent amount.
+        return (gas * gasPrice * (100 + serviceFee)) / 100;
+    }
+}

contracts/GSN/bouncers/GSNBouncerERC20Fee.sol

@@ -0,0 +1,143 @@
+pragma solidity ^0.5.0;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "./GSNBouncerBase.sol";
+import "../../math/SafeMath.sol";
+import "../../ownership/Secondary.sol";
+import "../../token/ERC20/SafeERC20.sol";
+import "../../token/ERC20/ERC20.sol";
+import "../../token/ERC20/ERC20Detailed.sol";
+
+contract GSNBouncerERC20Fee is Initializable, GSNBouncerBase {
+    using SafeERC20 for __unstable__ERC20PrimaryAdmin;
+    using SafeMath for uint256;
+
+    enum GSNBouncerERC20FeeErrorCodes {
+        INSUFFICIENT_BALANCE
+    }
+
+    // We use a random storage slot to allow proxy contracts to enable GSN support in an upgrade without changing their
+    // storage layout. This value is calculated as: keccak256('gsn.bouncer.signature.token'), minus 1.
+    bytes32 constant private TOKEN_STORAGE_SLOT = 0xd918b70a5a5c95a8c0cac8acbdd59e1b4acd0645f53c0461d64b41f8825c8828;
+
+    function initialize(string memory name, string memory symbol, uint8 decimals) public initializer {
+        // TODO: Should we inject this token, instead of creating it, in order to make it upgradeable?
+        // However, that would mean removing it from unstable and making in an official contract
+        _setToken(new __unstable__ERC20PrimaryAdmin(name, symbol, decimals));
+    }
+
+    function token() public view returns (IERC20) {
+        return IERC20(_getToken());
+    }
+
+    function _mint(address account, uint256 amount) internal {
+        _getToken().mint(account, amount);
+    }
+
+    function acceptRelayedCall(
+        address,
+        address from,
+        bytes calldata,
+        uint256 transactionFee,
+        uint256 gasPrice,
+        uint256,
+        uint256,
+        bytes calldata,
+        uint256 maxPossibleCharge
+    )
+        external
+        view
+        returns (uint256, bytes memory)
+    {
+        if (_getToken().balanceOf(from) < maxPossibleCharge) {
+            return _rejectRelayedCall(uint256(GSNBouncerERC20FeeErrorCodes.INSUFFICIENT_BALANCE));
+        }
+
+        return _approveRelayedCall(abi.encode(from, maxPossibleCharge, transactionFee, gasPrice));
+    }
+
+    function _preRelayedCall(bytes memory context) internal returns (bytes32) {
+        (address from, uint256 maxPossibleCharge) = abi.decode(context, (address, uint256));
+
+        // The maximum token charge is pre-charged from the user
+        _getToken().safeTransferFrom(from, address(this), maxPossibleCharge);
+    }
+
+    function _postRelayedCall(bytes memory context, bool, uint256 actualCharge, bytes32) internal {
+        (address from, uint256 maxPossibleCharge, uint256 transactionFee, uint256 gasPrice) =
+            abi.decode(context, (address, uint256, uint256, uint256));
+
+        // actualCharge is an _estimated_ charge, which assumes postRelayedCall will use all available gas.
+        // This implementation's gas cost can be roughly estimated as 10k gas, for the two SSTORE operations in an
+        // ERC20 transfer.
+        uint256 overestimation = _computeCharge(POST_RELAYED_CALL_MAX_GAS.sub(10000), gasPrice, transactionFee);
+        actualCharge = actualCharge.sub(overestimation);
+
+        // After the relayed call has been executed and the actual charge estimated, the excess pre-charge is returned
+        _getToken().safeTransfer(from, maxPossibleCharge.sub(actualCharge));
+    }
+
+    function _getToken() private view returns (__unstable__ERC20PrimaryAdmin token) {
+      bytes32 slot = TOKEN_STORAGE_SLOT;
+      // solhint-disable-next-line no-inline-assembly
+      assembly {
+        token := sload(slot)
+      }
+    }
+
+    function _setToken(__unstable__ERC20PrimaryAdmin token) private {
+      bytes32 slot = TOKEN_STORAGE_SLOT;
+      // solhint-disable-next-line no-inline-assembly
+      assembly {
+        sstore(slot, token)
+      }
+    }
+}
+
+/**
+ * @title __unstable__ERC20PrimaryAdmin
+ * @dev An ERC20 token owned by another contract, which has minting permissions and can use transferFrom to receive
+ * anyone's tokens. This contract is an internal helper for GSNRecipientERC20Fee, and should not be used
+ * outside of this context.
+ */
+// solhint-disable-next-line contract-name-camelcase
+contract __unstable__ERC20PrimaryAdmin is ERC20, ERC20Detailed, Secondary {
+    uint256 private constant UINT256_MAX = 2**256 - 1;
+
+    constructor(string memory name, string memory symbol, uint8 decimals) public {
+        Secondary.initialize(msg.sender);
+        ERC20Detailed.initialize(name, symbol, decimals);
+    }
+
+    // The primary account (GSNRecipientERC20Fee) can mint tokens
+    function mint(address account, uint256 amount) public onlyPrimary {
+        _mint(account, amount);
+    }
+
+    // The primary account has 'infinite' allowance for all token holders
+    function allowance(address owner, address spender) public view returns (uint256) {
+        if (spender == primary()) {
+            return UINT256_MAX;
+        } else {
+            return super.allowance(owner, spender);
+        }
+    }
+
+    // Allowance for the primary account cannot be changed (it is always 'infinite')
+    function _approve(address owner, address spender, uint256 value) internal {
+        if (spender == primary()) {
+            return;
+        } else {
+            super._approve(owner, spender, value);
+        }
+    }
+
+    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
+        if (recipient == primary()) {
+            _transfer(sender, recipient, amount);
+            return true;
+        } else {
+            return super.transferFrom(sender, recipient, amount);
+        }
+    }
+}

contracts/GSN/bouncers/GSNBouncerSignature.sol

@@ -0,0 +1,70 @@
+pragma solidity ^0.5.0;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "./GSNBouncerBase.sol";
+import "../../cryptography/ECDSA.sol";
+
+contract GSNBouncerSignature is Initializable, GSNBouncerBase {
+    using ECDSA for bytes32;
+
+    // We use a random storage slot to allow proxy contracts to enable GSN support in an upgrade without changing their
+    // storage layout. This value is calculated as: keccak256('gsn.bouncer.signature.trustedSigner'), minus 1.
+    bytes32 constant private TRUSTED_SIGNER_STORAGE_SLOT = 0xe7b237a4017a399d277819456dce32c2356236bbc518a6d84a9a8d1cfdf1e9c5;
+
+    enum GSNBouncerSignatureErrorCodes {
+        INVALID_SIGNER
+    }
+
+    function initialize(address trustedSigner) public initializer {
+        _setTrustedSigner(trustedSigner);
+    }
+
+    function acceptRelayedCall(
+        address relay,
+        address from,
+        bytes calldata encodedFunction,
+        uint256 transactionFee,
+        uint256 gasPrice,
+        uint256 gasLimit,
+        uint256 nonce,
+        bytes calldata approvalData,
+        uint256
+    )
+        external
+        view
+        returns (uint256, bytes memory)
+    {
+        bytes memory blob = abi.encodePacked(
+            relay,
+            from,
+            encodedFunction,
+            transactionFee,
+            gasPrice,
+            gasLimit,
+            nonce, // Prevents replays on RelayHub
+            getHubAddr(), // Prevents replays in multiple RelayHubs
+            address(this) // Prevents replays in multiple recipients
+        );
+        if (keccak256(blob).toEthSignedMessageHash().recover(approvalData) == _getTrustedSigner()) {
+            return _approveRelayedCall();
+        } else {
+            return _rejectRelayedCall(uint256(GSNBouncerSignatureErrorCodes.INVALID_SIGNER));
+        }
+    }
+
+    function _getTrustedSigner() private view returns (address trustedSigner) {
+      bytes32 slot = TRUSTED_SIGNER_STORAGE_SLOT;
+      // solhint-disable-next-line no-inline-assembly
+      assembly {
+        trustedSigner := sload(slot)
+      }
+    }
+
+    function _setTrustedSigner(address trustedSigner) private {
+      bytes32 slot = TRUSTED_SIGNER_STORAGE_SLOT;
+      // solhint-disable-next-line no-inline-assembly
+      assembly {
+        sstore(slot, trustedSigner)
+      }
+    }
+}

contracts/Killable.sol

@@ -1,15 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import "./Ownable.sol";
-
-
-/*
- * Killable
- * Base contract that can be killed by owner. All funds in contract will be sent to the owner.
- */
-contract Killable is Ownable {
-  function kill() onlyOwner {
-    selfdestruct(owner);
-  }
-}

contracts/LimitBalance.sol

@@ -1,27 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/**
- * LimitBalance
- * Simple contract to limit the balance of child contract.
- * Note this doesn't prevent other contracts to send funds 
- * by using selfdestruct(address);
- * See: https://github.com/ConsenSys/smart-contract-best-practices#remember-that-ether-can-be-forcibly-sent-to-an-account
- */
-contract LimitBalance {
-
-  uint public limit;
-
-  function LimitBalance(uint _limit) {
-    limit = _limit;
-  }
-
-  modifier limitedPayable() { 
-    if (this.balance > limit) {
-      throw;
-    }
-    _;
-    
-  }
-
-}

contracts/Migrations.sol

@@ -1,18 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import './Ownable.sol';
-
-
-contract Migrations is Ownable {
-  uint public lastCompletedMigration;
-
-  function setCompleted(uint completed) onlyOwner {
-    lastCompletedMigration = completed;
-  }
-
-  function upgrade(address newAddress) onlyOwner {
-    Migrations upgraded = Migrations(newAddress);
-    upgraded.setCompleted(lastCompletedMigration);
-  }
-}

contracts/Multisig.sol

@@ -1,29 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/*
- * Multisig
- * Interface contract for multisig proxy contracts; see below for docs.
- */
-contract Multisig {
-  // EVENTS
-
-  // logged events:
-  // Funds has arrived into the wallet (record how much).
-  event Deposit(address _from, uint value);
-  // Single transaction going out of the wallet (record who signed for it, how much, and to whom it's going).
-  event SingleTransact(address owner, uint value, address to, bytes data);
-  // Multi-sig transaction going out of the wallet (record who signed for it last, the operation hash, how much, and to whom it's going).
-  event MultiTransact(address owner, bytes32 operation, uint value, address to, bytes data);
-  // Confirmation still needed for a transaction.
-  event ConfirmationNeeded(bytes32 operation, address initiator, uint value, address to, bytes data);
-
-
-  // FUNCTIONS
-
-  // TODO: document
-  function changeOwner(address _from, address _to) external;
-  function execute(address _to, uint _value, bytes _data) external returns (bytes32);
-  function confirm(bytes32 _h) returns (bool);
-}
-

contracts/MultisigWallet.sol

@@ -1,110 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import "./Multisig.sol";
-import "./Shareable.sol";
-import "./DayLimit.sol";
-
-
-/*
- * MultisigWallet
- * usage:
- * bytes32 h = Wallet(w).from(oneOwner).execute(to, value, data);
- * Wallet(w).from(anotherOwner).confirm(h);
- */
-contract MultisigWallet is Multisig, Shareable, DayLimit {
-  // TYPES
-
-  // Transaction structure to remember details of transaction lest it need be saved for a later call.
-  struct Transaction {
-    address to;
-    uint value;
-    bytes data;
-  }
-
-
-  // CONSTRUCTOR
-
-  // just pass on the owner array to the multiowned and
-  // the limit to daylimit
-  function MultisigWallet(address[] _owners, uint _required, uint _daylimit)
-    Shareable(_owners, _required)
-    DayLimit(_daylimit) { }
-
-
-  // METHODS
-
-  // kills the contract sending everything to `_to`.
-  function kill(address _to) onlymanyowners(sha3(msg.data)) external {
-    suicide(_to);
-  }
-
-  // gets called when no other function matches
-  function() payable {
-    // just being sent some cash?
-    if (msg.value > 0)
-      Deposit(msg.sender, msg.value);
-  }
-
-  // Outside-visible transact entry point. Executes transaction immediately if below daily spend limit.
-  // If not, goes into multisig process. We provide a hash on return to allow the sender to provide
-  // shortcuts for the other confirmations (allowing them to avoid replicating the _to, _value
-  // and _data arguments). They still get the option of using them if they want, anyways.
-  function execute(address _to, uint _value, bytes _data) external onlyOwner returns (bytes32 _r) {
-    // first, take the opportunity to check that we're under the daily limit.
-    if (underLimit(_value)) {
-      SingleTransact(msg.sender, _value, _to, _data);
-      // yes - just execute the call.
-      if (!_to.call.value(_value)(_data)) {
-        throw;
-      }
-      return 0;
-    }
-    // determine our operation hash.
-    _r = sha3(msg.data, block.number);
-    if (!confirm(_r) && txs[_r].to == 0) {
-      txs[_r].to = _to;
-      txs[_r].value = _value;
-      txs[_r].data = _data;
-      ConfirmationNeeded(_r, msg.sender, _value, _to, _data);
-    }
-  }
-
-  // confirm a transaction through just the hash. we use the previous transactions map, txs, in order
-  // to determine the body of the transaction from the hash provided.
-  function confirm(bytes32 _h) onlymanyowners(_h) returns (bool) {
-    if (txs[_h].to != 0) {
-      if (!txs[_h].to.call.value(txs[_h].value)(txs[_h].data)) {
-        throw;
-      }
-      MultiTransact(msg.sender, _h, txs[_h].value, txs[_h].to, txs[_h].data);
-      delete txs[_h];
-      return true;
-    }
-  }
-
-  function setDailyLimit(uint _newLimit) onlymanyowners(sha3(msg.data)) external {
-    _setDailyLimit(_newLimit);
-  }
-
-  function resetSpentToday() onlymanyowners(sha3(msg.data)) external {
-    _resetSpentToday();
-  }
-
-
-  // INTERNAL METHODS
-
-  function clearPending() internal {
-    uint length = pendingsIndex.length;
-    for (uint i = 0; i < length; ++i) {
-      delete txs[pendingsIndex[i]];
-    }
-    super.clearPending();
-  }
-
-
-  // FIELDS
-
-  // pending transactions we have at present.
-  mapping (bytes32 => Transaction) txs;
-}

contracts/Ownable.sol

@@ -1,26 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/*
- * Ownable
- *
- * Base contract with an owner.
- * Provides onlyOwner modifier, which prevents function from running if it is called by anyone other than the owner.
- */
-contract Ownable {
-  address public owner;
-
-  function Ownable() {
-    owner = msg.sender;
-  }
-
-  modifier onlyOwner() {
-    if (msg.sender == owner)
-      _;
-  }
-
-  function transferOwnership(address newOwner) onlyOwner {
-    if (newOwner != address(0)) owner = newOwner;
-  }
-
-}

contracts/PullPayment.sol

@@ -1,30 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/*
- * PullPayment
- * Base contract supporting async send for pull payments.
- * Inherit from this contract and use asyncSend instead of send.
- */
-contract PullPayment {
-  mapping(address => uint) public payments;
-
-  // store sent amount as credit to be pulled, called by payer
-  function asyncSend(address dest, uint amount) internal {
-    payments[dest] += amount;
-  }
-
-  // withdraw accumulated balance, called by payee
-  function withdrawPayments() {
-    address payee = msg.sender;
-    uint payment = payments[payee];
-    
-    if (payment == 0) throw;
-    if (this.balance < payment) throw;
-
-    payments[payee] = 0;
-    if (!payee.send(payment)) {
-      throw;
-    }
-  }
-}

contracts/SafeMath.sol

@@ -1,29 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/**
- * Math operations with safety checks
- */
-contract SafeMath {
-  function safeMul(uint a, uint b) internal returns (uint) {
-    uint c = a * b;
-    assert(a == 0 || c / a == b);
-    return c;
-  }
-
-  function safeSub(uint a, uint b) internal returns (uint) {
-    assert(b <= a);
-    return a - b;
-  }
-
-  function safeAdd(uint a, uint b) internal returns (uint) {
-    uint c = a + b;
-    assert(c>=a && c>=b);
-    return c;
-  }
-
-  function assert(bool assertion) internal {
-    if (!assertion) throw;
-  }
-}
-

contracts/Shareable.sol

@@ -1,164 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/*
- * Shareable
- *
- * Based on https://github.com/ethereum/dapp-bin/blob/master/wallet/wallet.sol
- *
- * inheritable "property" contract that enables methods to be protected by requiring the acquiescence of either a single, or, crucially, each of a number of, designated owners.
- *
- * usage:
- * use modifiers onlyowner (just own owned) or onlymanyowners(hash), whereby the same hash must be provided by some number (specified in constructor) of the set of owners (specified in the constructor) before the interior is executed.
- */
-contract Shareable {
-  // TYPES
-
-  // struct for the status of a pending operation.
-  struct PendingState {
-    uint yetNeeded;
-    uint ownersDone;
-    uint index;
-  }
-
-
-  // FIELDS
-
-  // the number of owners that must confirm the same operation before it is run.
-  uint public required;
-
-  // list of owners
-  uint[256] owners;
-  uint constant c_maxOwners = 250;
-  // index on the list of owners to allow reverse lookup
-  mapping(uint => uint) ownerIndex;
-  // the ongoing operations.
-  mapping(bytes32 => PendingState) pendings;
-  bytes32[] pendingsIndex;
-
-
-  // EVENTS
-
-  // this contract only has six types of events: it can accept a confirmation, in which case
-  // we record owner and operation (hash) alongside it.
-  event Confirmation(address owner, bytes32 operation);
-  event Revoke(address owner, bytes32 operation);
-
-
-  // MODIFIERS
-
-  // simple single-sig function modifier.
-  modifier onlyOwner {
-    if (isOwner(msg.sender))
-      _;
-  }
-
-  // multi-sig function modifier: the operation must have an intrinsic hash in order
-  // that later attempts can be realised as the same underlying operation and
-  // thus count as confirmations.
-  modifier onlymanyowners(bytes32 _operation) {
-    if (confirmAndCheck(_operation))
-      _;
-  }
-
-
-  // CONSTRUCTOR
-
-  // constructor is given number of sigs required to do protected "onlymanyowners" transactions
-  // as well as the selection of addresses capable of confirming them.
-  function Shareable(address[] _owners, uint _required) {
-    owners[1] = uint(msg.sender);
-    ownerIndex[uint(msg.sender)] = 1;
-    for (uint i = 0; i < _owners.length; ++i) {
-      owners[2 + i] = uint(_owners[i]);
-      ownerIndex[uint(_owners[i])] = 2 + i;
-    }
-    required = _required;
-  }
-
-
-  // METHODS
-
-  // Revokes a prior confirmation of the given operation
-  function revoke(bytes32 _operation) external {
-    uint index = ownerIndex[uint(msg.sender)];
-    // make sure they're an owner
-    if (index == 0) return;
-    uint ownerIndexBit = 2**index;
-    var pending = pendings[_operation];
-    if (pending.ownersDone & ownerIndexBit > 0) {
-      pending.yetNeeded++;
-      pending.ownersDone -= ownerIndexBit;
-      Revoke(msg.sender, _operation);
-    }
-  }
-
-  // Gets an owner by 0-indexed position (using numOwners as the count)
-  function getOwner(uint ownerIndex) external constant returns (address) {
-    return address(owners[ownerIndex + 1]);
-  }
-
-  function isOwner(address _addr) constant returns (bool) {
-    return ownerIndex[uint(_addr)] > 0;
-  }
-
-  function hasConfirmed(bytes32 _operation, address _owner) constant returns (bool) {
-    var pending = pendings[_operation];
-    uint index = ownerIndex[uint(_owner)];
-
-    // make sure they're an owner
-    if (index == 0) return false;
-
-    // determine the bit to set for this owner.
-    uint ownerIndexBit = 2**index;
-    return !(pending.ownersDone & ownerIndexBit == 0);
-  }
-
-  // INTERNAL METHODS
-
-  function confirmAndCheck(bytes32 _operation) internal returns (bool) {
-    // determine what index the present sender is:
-    uint index = ownerIndex[uint(msg.sender)];
-    // make sure they're an owner
-    if (index == 0) return;
-
-    var pending = pendings[_operation];
-    // if we're not yet working on this operation, switch over and reset the confirmation status.
-    if (pending.yetNeeded == 0) {
-      // reset count of confirmations needed.
-      pending.yetNeeded = required;
-      // reset which owners have confirmed (none) - set our bitmap to 0.
-      pending.ownersDone = 0;
-      pending.index = pendingsIndex.length++;
-      pendingsIndex[pending.index] = _operation;
-    }
-    // determine the bit to set for this owner.
-    uint ownerIndexBit = 2**index;
-    // make sure we (the message sender) haven't confirmed this operation previously.
-    if (pending.ownersDone & ownerIndexBit == 0) {
-      Confirmation(msg.sender, _operation);
-      // ok - check if count is enough to go ahead.
-      if (pending.yetNeeded <= 1) {
-        // enough confirmations: reset and run interior.
-        delete pendingsIndex[pendings[_operation].index];
-        delete pendings[_operation];
-        return true;
-      }
-      else
-        {
-          // not enough: record that this owner in particular confirmed.
-          pending.yetNeeded--;
-          pending.ownersDone |= ownerIndexBit;
-        }
-    }
-  }
-
-  function clearPending() internal {
-    uint length = pendingsIndex.length;
-    for (uint i = 0; i < length; ++i)
-    if (pendingsIndex[i] != 0)
-      delete pendings[pendingsIndex[i]];
-    delete pendingsIndex;
-  }
-
-}

contracts/Stoppable.sol

@@ -1,28 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import "./Ownable.sol";
-
-
-/*
- * Stoppable
- * Abstract contract that allows children to implement an
- * emergency stop mechanism.
- */
-contract Stoppable is Ownable {
-  bool public stopped;
-
-  modifier stopInEmergency { if (!stopped) _; }
-  modifier onlyInEmergency { if (stopped) _; }
-
-  // called by the owner on emergency, triggers stopped state
-  function emergencyStop() external onlyOwner {
-    stopped = true;
-  }
-
-  // called by the owner on end of emergency, returns to normal state
-  function release() external onlyOwner onlyInEmergency {
-    stopped = false;
-  }
-
-}

contracts/access/Roles.sol

@@ -0,0 +1,40 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title Roles
+ * @dev Library for managing addresses assigned to a Role.
+ */
+library Roles {
+    struct Role {
+        mapping (address => bool) bearer;
+    }
+
+    /**
+     * @dev give an account access to this role
+     */
+    function add(Role storage role, address account) internal {
+        require(account != address(0));
+        require(!has(role, account));
+
+        role.bearer[account] = true;
+    }
+
+    /**
+     * @dev remove an account's access to this role
+     */
+    function remove(Role storage role, address account) internal {
+        require(account != address(0));
+        require(has(role, account));
+
+        role.bearer[account] = false;
+    }
+
+    /**
+     * @dev check if an account has this role
+     * @return bool
+     */
+    function has(Role storage role, address account) internal view returns (bool) {
+        require(account != address(0));
+        return role.bearer[account];
+    }
+}

contracts/access/roles/CapperRole.sol

@@ -0,0 +1,50 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../Roles.sol";
+
+contract CapperRole is Initializable, Context {
+    using Roles for Roles.Role;
+
+    event CapperAdded(address indexed account);
+    event CapperRemoved(address indexed account);
+
+    Roles.Role private _cappers;
+
+    function initialize(address sender) public initializer {
+        if (!isCapper(sender)) {
+            _addCapper(sender);
+        }
+    }
+
+    modifier onlyCapper() {
+        require(isCapper(_msgSender()), "CapperRole: caller does not have the Capper role");
+        _;
+    }
+
+    function isCapper(address account) public view returns (bool) {
+        return _cappers.has(account);
+    }
+
+    function addCapper(address account) public onlyCapper {
+        _addCapper(account);
+    }
+
+    function renounceCapper() public {
+        _removeCapper(_msgSender());
+    }
+
+    function _addCapper(address account) internal {
+        _cappers.add(account);
+        emit CapperAdded(account);
+    }
+
+    function _removeCapper(address account) internal {
+        _cappers.remove(account);
+        emit CapperRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/access/roles/MinterRole.sol

@@ -0,0 +1,50 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../Roles.sol";
+
+contract MinterRole is Initializable, Context {
+    using Roles for Roles.Role;
+
+    event MinterAdded(address indexed account);
+    event MinterRemoved(address indexed account);
+
+    Roles.Role private _minters;
+
+    function initialize(address sender) public initializer {
+        if (!isMinter(sender)) {
+            _addMinter(sender);
+        }
+    }
+
+    modifier onlyMinter() {
+        require(isMinter(_msgSender()), "MinterRole: caller does not have the Minter role");
+        _;
+    }
+
+    function isMinter(address account) public view returns (bool) {
+        return _minters.has(account);
+    }
+
+    function addMinter(address account) public onlyMinter {
+        _addMinter(account);
+    }
+
+    function renounceMinter() public {
+        _removeMinter(_msgSender());
+    }
+
+    function _addMinter(address account) internal {
+        _minters.add(account);
+        emit MinterAdded(account);
+    }
+
+    function _removeMinter(address account) internal {
+        _minters.remove(account);
+        emit MinterRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/access/roles/PauserRole.sol

@@ -0,0 +1,50 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../Roles.sol";
+
+contract PauserRole is Initializable, Context {
+    using Roles for Roles.Role;
+
+    event PauserAdded(address indexed account);
+    event PauserRemoved(address indexed account);
+
+    Roles.Role private _pausers;
+
+    function initialize(address sender) public initializer {
+        if (!isPauser(sender)) {
+            _addPauser(sender);
+        }
+    }
+
+    modifier onlyPauser() {
+        require(isPauser(_msgSender()), "PauserRole: caller does not have the Pauser role");
+        _;
+    }
+
+    function isPauser(address account) public view returns (bool) {
+        return _pausers.has(account);
+    }
+
+    function addPauser(address account) public onlyPauser {
+        _addPauser(account);
+    }
+
+    function renouncePauser() public {
+        _removePauser(_msgSender());
+    }
+
+    function _addPauser(address account) internal {
+        _pausers.add(account);
+        emit PauserAdded(account);
+    }
+
+    function _removePauser(address account) internal {
+        _pausers.remove(account);
+        emit PauserRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/access/roles/SignerRole.sol

@@ -0,0 +1,50 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../Roles.sol";
+
+contract SignerRole is Initializable, Context {
+    using Roles for Roles.Role;
+
+    event SignerAdded(address indexed account);
+    event SignerRemoved(address indexed account);
+
+    Roles.Role private _signers;
+
+    function initialize(address sender) public initializer {
+        if (!isSigner(sender)) {
+            _addSigner(sender);
+        }
+    }
+
+    modifier onlySigner() {
+        require(isSigner(_msgSender()), "SignerRole: caller does not have the Signer role");
+        _;
+    }
+
+    function isSigner(address account) public view returns (bool) {
+        return _signers.has(account);
+    }
+
+    function addSigner(address account) public onlySigner {
+        _addSigner(account);
+    }
+
+    function renounceSigner() public {
+        _removeSigner(_msgSender());
+    }
+
+    function _addSigner(address account) internal {
+        _signers.add(account);
+        emit SignerAdded(account);
+    }
+
+    function _removeSigner(address account) internal {
+        _signers.remove(account);
+        emit SignerRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/access/roles/WhitelistAdminRole.sol

@@ -0,0 +1,54 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../Roles.sol";
+
+/**
+ * @title WhitelistAdminRole
+ * @dev WhitelistAdmins are responsible for assigning and removing Whitelisted accounts.
+ */
+contract WhitelistAdminRole is Initializable, Context {
+    using Roles for Roles.Role;
+
+    event WhitelistAdminAdded(address indexed account);
+    event WhitelistAdminRemoved(address indexed account);
+
+    Roles.Role private _whitelistAdmins;
+
+    function initialize(address sender) public initializer {
+        if (!isWhitelistAdmin(sender)) {
+            _addWhitelistAdmin(sender);
+        }
+    }
+
+    modifier onlyWhitelistAdmin() {
+        require(isWhitelistAdmin(_msgSender()), "WhitelistAdminRole: caller does not have the WhitelistAdmin role");
+        _;
+    }
+
+    function isWhitelistAdmin(address account) public view returns (bool) {
+        return _whitelistAdmins.has(account);
+    }
+
+    function addWhitelistAdmin(address account) public onlyWhitelistAdmin {
+        _addWhitelistAdmin(account);
+    }
+
+    function renounceWhitelistAdmin() public {
+        _removeWhitelistAdmin(_msgSender());
+    }
+
+    function _addWhitelistAdmin(address account) internal {
+        _whitelistAdmins.add(account);
+        emit WhitelistAdminAdded(account);
+    }
+
+    function _removeWhitelistAdmin(address account) internal {
+        _whitelistAdmins.remove(account);
+        emit WhitelistAdminRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/access/roles/WhitelistedRole.sol

@@ -0,0 +1,59 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../Roles.sol";
+import "./WhitelistAdminRole.sol";
+
+/**
+ * @title WhitelistedRole
+ * @dev Whitelisted accounts have been approved by a WhitelistAdmin to perform certain actions (e.g. participate in a
+ * crowdsale). This role is special in that the only accounts that can add it are WhitelistAdmins (who can also remove
+ * it), and not Whitelisteds themselves.
+ */
+contract WhitelistedRole is Initializable, Context, WhitelistAdminRole {
+    using Roles for Roles.Role;
+
+    event WhitelistedAdded(address indexed account);
+    event WhitelistedRemoved(address indexed account);
+
+    Roles.Role private _whitelisteds;
+
+    modifier onlyWhitelisted() {
+        require(isWhitelisted(_msgSender()), "WhitelistedRole: caller does not have the Whitelisted role");
+        _;
+    }
+
+    function initialize(address sender) public initializer {
+        WhitelistAdminRole.initialize(sender);
+    }
+
+    function isWhitelisted(address account) public view returns (bool) {
+        return _whitelisteds.has(account);
+    }
+
+    function addWhitelisted(address account) public onlyWhitelistAdmin {
+        _addWhitelisted(account);
+    }
+
+    function removeWhitelisted(address account) public onlyWhitelistAdmin {
+        _removeWhitelisted(account);
+    }
+
+    function renounceWhitelisted() public {
+        _removeWhitelisted(_msgSender());
+    }
+
+    function _addWhitelisted(address account) internal {
+        _whitelisteds.add(account);
+        emit WhitelistedAdded(account);
+    }
+
+    function _removeWhitelisted(address account) internal {
+        _whitelisteds.remove(account);
+        emit WhitelistedRemoved(account);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/Crowdsale.sol

@@ -0,0 +1,207 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../GSN/Context.sol";
+import "../token/ERC20/IERC20.sol";
+import "../math/SafeMath.sol";
+import "../token/ERC20/SafeERC20.sol";
+import "../utils/ReentrancyGuard.sol";
+
+/**
+ * @title Crowdsale
+ * @dev Crowdsale is a base contract for managing a token crowdsale,
+ * allowing investors to purchase tokens with ether. This contract implements
+ * such functionality in its most fundamental form and can be extended to provide additional
+ * functionality and/or custom behavior.
+ * The external interface represents the basic interface for purchasing tokens, and conforms
+ * the base architecture for crowdsales. It is *not* intended to be modified / overridden.
+ * The internal interface conforms the extensible and modifiable surface of crowdsales. Override
+ * the methods to add functionality. Consider using 'super' where appropriate to concatenate
+ * behavior.
+ */
+contract Crowdsale is Initializable, Context, ReentrancyGuard {
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
+
+    // The token being sold
+    IERC20 private _token;
+
+    // Address where funds are collected
+    address payable private _wallet;
+
+    // How many token units a buyer gets per wei.
+    // The rate is the conversion between wei and the smallest and indivisible token unit.
+    // So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK
+    // 1 wei will give you 1 unit, or 0.001 TOK.
+    uint256 private _rate;
+
+    // Amount of wei raised
+    uint256 private _weiRaised;
+
+    /**
+     * Event for token purchase logging
+     * @param purchaser who paid for the tokens
+     * @param beneficiary who got the tokens
+     * @param value weis paid for purchase
+     * @param amount amount of tokens purchased
+     */
+    event TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);
+
+    /**
+     * @param rate Number of token units a buyer gets per wei
+     * @dev The rate is the conversion between wei and the smallest and indivisible
+     * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
+     * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
+     * @param wallet Address where collected funds will be forwarded to
+     * @param token Address of the token being sold
+     */
+    function initialize(uint256 rate, address payable wallet, IERC20 token) public initializer {
+        require(rate > 0);
+        require(wallet != address(0));
+        require(address(token) != address(0));
+
+        _rate = rate;
+        _wallet = wallet;
+        _token = token;
+    }
+
+    /**
+     * @dev fallback function ***DO NOT OVERRIDE***
+     * Note that other contracts will transfer funds with a base gas stipend
+     * of 2300, which is not enough to call buyTokens. Consider calling
+     * buyTokens directly when purchasing tokens from a contract.
+     */
+    function () external payable {
+        buyTokens(_msgSender());
+    }
+
+    /**
+     * @return the token being sold.
+     */
+    function token() public view returns (IERC20) {
+        return _token;
+    }
+
+    /**
+     * @return the address where funds are collected.
+     */
+    function wallet() public view returns (address payable) {
+        return _wallet;
+    }
+
+    /**
+     * @return the number of token units a buyer gets per wei.
+     */
+    function rate() public view returns (uint256) {
+        return _rate;
+    }
+
+    /**
+     * @return the amount of wei raised.
+     */
+    function weiRaised() public view returns (uint256) {
+        return _weiRaised;
+    }
+
+    /**
+     * @dev low level token purchase ***DO NOT OVERRIDE***
+     * This function has a non-reentrancy guard, so it shouldn't be called by
+     * another `nonReentrant` function.
+     * @param beneficiary Recipient of the token purchase
+     */
+    function buyTokens(address beneficiary) public nonReentrant payable {
+        uint256 weiAmount = msg.value;
+        _preValidatePurchase(beneficiary, weiAmount);
+
+        // calculate token amount to be created
+        uint256 tokens = _getTokenAmount(weiAmount);
+
+        // update state
+        _weiRaised = _weiRaised.add(weiAmount);
+
+        _processPurchase(beneficiary, tokens);
+        emit TokensPurchased(_msgSender(), beneficiary, weiAmount, tokens);
+
+        _updatePurchasingState(beneficiary, weiAmount);
+
+        _forwardFunds();
+        _postValidatePurchase(beneficiary, weiAmount);
+    }
+
+    function _hasBeenInitialized() internal view returns (bool) {
+        return ((_rate > 0) && (_wallet != address(0)) && (address(_token) != address(0)));
+    }
+
+    /**
+     * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
+     * Use `super` in contracts that inherit from Crowdsale to extend their validations.
+     * Example from CappedCrowdsale.sol's _preValidatePurchase method:
+     *     super._preValidatePurchase(beneficiary, weiAmount);
+     *     require(weiRaised().add(weiAmount) <= cap);
+     * @param beneficiary Address performing the token purchase
+     * @param weiAmount Value in wei involved in the purchase
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        require(beneficiary != address(0));
+        require(weiAmount != 0);
+    }
+
+    /**
+     * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid
+     * conditions are not met.
+     * @param beneficiary Address performing the token purchase
+     * @param weiAmount Value in wei involved in the purchase
+     */
+    function _postValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    /**
+     * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends
+     * its tokens.
+     * @param beneficiary Address performing the token purchase
+     * @param tokenAmount Number of tokens to be emitted
+     */
+    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
+        _token.safeTransfer(beneficiary, tokenAmount);
+    }
+
+    /**
+     * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send
+     * tokens.
+     * @param beneficiary Address receiving the tokens
+     * @param tokenAmount Number of tokens to be purchased
+     */
+    function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
+        _deliverTokens(beneficiary, tokenAmount);
+    }
+
+    /**
+     * @dev Override for extensions that require an internal state to check for validity (current user contributions,
+     * etc.)
+     * @param beneficiary Address receiving the tokens
+     * @param weiAmount Value in wei involved in the purchase
+     */
+    function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    /**
+     * @dev Override to extend the way in which ether is converted to tokens.
+     * @param weiAmount Value in wei to be converted into tokens
+     * @return Number of tokens that can be purchased with the specified _weiAmount
+     */
+    function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
+        return weiAmount.mul(_rate);
+    }
+
+    /**
+     * @dev Determines how ETH is stored/forwarded on purchases.
+     */
+    function _forwardFunds() internal {
+        _wallet.transfer(msg.value);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/distribution/FinalizableCrowdsale.sol

@@ -0,0 +1,50 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../../math/SafeMath.sol";
+import "../validation/TimedCrowdsale.sol";
+
+/**
+ * @title FinalizableCrowdsale
+ * @dev Extension of TimedCrowdsale with a one-off finalization action, where one
+ * can do extra work after finishing.
+ */
+contract FinalizableCrowdsale is Initializable, TimedCrowdsale {
+    using SafeMath for uint256;
+
+    bool private _finalized;
+
+    event CrowdsaleFinalized();
+
+    /**
+     * @return true if the crowdsale is finalized, false otherwise.
+     */
+    function finalized() public view returns (bool) {
+        return _finalized;
+    }
+
+    /**
+     * @dev Must be called after crowdsale ends, to do some extra finalization
+     * work. Calls the contract's finalization function.
+     */
+    function finalize() public {
+        require(!_finalized);
+        require(hasClosed());
+
+        _finalized = true;
+
+        _finalization();
+        emit CrowdsaleFinalized();
+    }
+
+    /**
+     * @dev Can be overridden to add finalization logic. The overriding function
+     * should call super._finalization() to ensure the chain of finalization is
+     * executed entirely.
+     */
+    function _finalization() internal {
+        // solhint-disable-previous-line no-empty-blocks
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol

@@ -0,0 +1,45 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../validation/TimedCrowdsale.sol";
+import "../../math/SafeMath.sol";
+
+/**
+ * @title PostDeliveryCrowdsale
+ * @dev Crowdsale that locks tokens from withdrawal until it ends.
+ */
+contract PostDeliveryCrowdsale is Initializable, TimedCrowdsale {
+    using SafeMath for uint256;
+
+    mapping(address => uint256) private _balances;
+
+    /**
+     * @dev Withdraw tokens only after crowdsale ends.
+     * @param beneficiary Whose tokens will be withdrawn.
+     */
+    function withdrawTokens(address beneficiary) public {
+        require(hasClosed());
+        uint256 amount = _balances[beneficiary];
+        require(amount > 0);
+        _balances[beneficiary] = 0;
+        _deliverTokens(beneficiary, amount);
+    }
+
+    /**
+     * @return the balance of an account.
+     */
+    function balanceOf(address account) public view returns (uint256) {
+        return _balances[account];
+    }
+
+    /**
+     * @dev Overrides parent by storing balances instead of issuing tokens right away.
+     * @param beneficiary Token purchaser
+     * @param tokenAmount Amount of tokens purchased
+     */
+    function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
+        _balances[beneficiary] = _balances[beneficiary].add(tokenAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/distribution/RefundableCrowdsale.sol

@@ -0,0 +1,94 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../../GSN/Context.sol";
+import "../../math/SafeMath.sol";
+import "./FinalizableCrowdsale.sol";
+import "../../payment/escrow/RefundEscrow.sol";
+
+/**
+ * @title RefundableCrowdsale
+ * @dev Extension of FinalizableCrowdsale contract that adds a funding goal, and the possibility of users
+ * getting a refund if goal is not met.
+ *
+ * Deprecated, use RefundablePostDeliveryCrowdsale instead. Note that if you allow tokens to be traded before the goal
+ * is met, then an attack is possible in which the attacker purchases tokens from the crowdsale and when they sees that
+ * the goal is unlikely to be met, they sell their tokens (possibly at a discount). The attacker will be refunded when
+ * the crowdsale is finalized, and the users that purchased from them will be left with worthless tokens.
+ */
+contract RefundableCrowdsale is Initializable, Context, FinalizableCrowdsale {
+    using SafeMath for uint256;
+
+    // minimum amount of funds to be raised in weis
+    uint256 private _goal;
+
+    // refund escrow used to hold funds while crowdsale is running
+    RefundEscrow private _escrow;
+
+    /**
+     * @dev Constructor, creates RefundEscrow.
+     * @param goal Funding goal
+     */
+    function initialize(uint256 goal) public initializer {
+        // FinalizableCrowdsale depends on TimedCrowdsale
+        assert(TimedCrowdsale._hasBeenInitialized());
+
+        require(goal > 0);
+        // conditional added to make initializer idempotent in case of diamond inheritance
+        if (address(_escrow) == address(0)) {
+            _escrow = new RefundEscrow();
+            _escrow.initialize(wallet(), address(this));
+        }
+        _goal = goal;
+    }
+
+    /**
+     * @return minimum amount of funds to be raised in wei.
+     */
+    function goal() public view returns (uint256) {
+        return _goal;
+    }
+
+    /**
+     * @dev Investors can claim refunds here if crowdsale is unsuccessful
+     * @param refundee Whose refund will be claimed.
+     */
+    function claimRefund(address payable refundee) public {
+        require(finalized());
+        require(!goalReached());
+
+        _escrow.withdraw(refundee);
+    }
+
+    /**
+     * @dev Checks whether funding goal was reached.
+     * @return Whether funding goal was reached
+     */
+    function goalReached() public view returns (bool) {
+        return weiRaised() >= _goal;
+    }
+
+    /**
+     * @dev escrow finalization task, called when finalize() is called
+     */
+    function _finalization() internal {
+        if (goalReached()) {
+            _escrow.close();
+            _escrow.beneficiaryWithdraw();
+        } else {
+            _escrow.enableRefunds();
+        }
+
+        super._finalization();
+    }
+
+    /**
+     * @dev Overrides Crowdsale fund forwarding, sending funds to escrow.
+     */
+    function _forwardFunds() internal {
+        _escrow.deposit.value(msg.value)(_msgSender());
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/distribution/RefundablePostDeliveryCrowdsale.sol

@@ -0,0 +1,23 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "./RefundableCrowdsale.sol";
+import "./PostDeliveryCrowdsale.sol";
+
+/**
+ * @title RefundablePostDeliveryCrowdsale
+ * @dev Extension of RefundableCrowdsale contract that only delivers the tokens
+ * once the crowdsale has closed and the goal met, preventing refunds to be issued
+ * to token holders.
+ */
+contract RefundablePostDeliveryCrowdsale is Initializable, RefundableCrowdsale, PostDeliveryCrowdsale {
+    function withdrawTokens(address beneficiary) public {
+        require(finalized());
+        require(goalReached());
+
+        super.withdrawTokens(beneficiary);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/emission/AllowanceCrowdsale.sol

@@ -0,0 +1,56 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../Crowdsale.sol";
+import "../../token/ERC20/IERC20.sol";
+import "../../token/ERC20/SafeERC20.sol";
+import "../../math/SafeMath.sol";
+import "../../math/Math.sol";
+
+/**
+ * @title AllowanceCrowdsale
+ * @dev Extension of Crowdsale where tokens are held by a wallet, which approves an allowance to the crowdsale.
+ */
+contract AllowanceCrowdsale is Initializable, Crowdsale {
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
+
+    address private _tokenWallet;
+
+    /**
+     * @dev Constructor, takes token wallet address.
+     * @param tokenWallet Address holding the tokens, which has approved allowance to the crowdsale
+     */
+    function initialize(address tokenWallet) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
+
+        require(tokenWallet != address(0));
+        _tokenWallet = tokenWallet;
+    }
+
+    /**
+     * @return the address of the wallet that will hold the tokens.
+     */
+    function tokenWallet() public view returns (address) {
+        return _tokenWallet;
+    }
+
+    /**
+     * @dev Checks the amount of tokens left in the allowance.
+     * @return Amount of tokens left in the allowance
+     */
+    function remainingTokens() public view returns (uint256) {
+        return Math.min(token().balanceOf(_tokenWallet), token().allowance(_tokenWallet, address(this)));
+    }
+
+    /**
+     * @dev Overrides parent behavior by transferring tokens from wallet.
+     * @param beneficiary Token purchaser
+     * @param tokenAmount Amount of tokens purchased
+     */
+    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
+        token().safeTransferFrom(_tokenWallet, beneficiary, tokenAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/emission/MintedCrowdsale.sol

@@ -0,0 +1,24 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../Crowdsale.sol";
+import "../../token/ERC20/ERC20Mintable.sol";
+
+/**
+ * @title MintedCrowdsale
+ * @dev Extension of Crowdsale contract whose tokens are minted in each purchase.
+ * Token ownership should be transferred to MintedCrowdsale for minting.
+ */
+contract MintedCrowdsale is Initializable, Crowdsale {
+    /**
+     * @dev Overrides delivery by minting tokens upon purchase.
+     * @param beneficiary Token purchaser
+     * @param tokenAmount Number of tokens to be minted
+     */
+    function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
+        // Potentially dangerous assumption about the type of the token.
+        require(ERC20Mintable(address(token())).mint(beneficiary, tokenAmount));
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/price/IncreasingPriceCrowdsale.sol

@@ -0,0 +1,83 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../validation/TimedCrowdsale.sol";
+import "../../math/SafeMath.sol";
+
+/**
+ * @title IncreasingPriceCrowdsale
+ * @dev Extension of Crowdsale contract that increases the price of tokens linearly in time.
+ * Note that what should be provided to the constructor is the initial and final _rates_, that is,
+ * the amount of tokens per wei contributed. Thus, the initial rate must be greater than the final rate.
+ */
+contract IncreasingPriceCrowdsale is Initializable, TimedCrowdsale {
+    using SafeMath for uint256;
+
+    uint256 private _initialRate;
+    uint256 private _finalRate;
+
+    /**
+     * @dev Constructor, takes initial and final rates of tokens received per wei contributed.
+     * @param initialRate Number of tokens a buyer gets per wei at the start of the crowdsale
+     * @param finalRate Number of tokens a buyer gets per wei at the end of the crowdsale
+     */
+    function initialize(uint256 initialRate, uint256 finalRate) public initializer {
+        assert(TimedCrowdsale._hasBeenInitialized());
+
+        require(finalRate > 0);
+        require(initialRate > finalRate);
+        _initialRate = initialRate;
+        _finalRate = finalRate;
+    }
+
+    /**
+     * The base rate function is overridden to revert, since this crowdsale doesn't use it, and
+     * all calls to it are a mistake.
+     */
+    function rate() public view returns (uint256) {
+        revert();
+    }
+
+    /**
+     * @return the initial rate of the crowdsale.
+     */
+    function initialRate() public view returns (uint256) {
+        return _initialRate;
+    }
+
+    /**
+     * @return the final rate of the crowdsale.
+     */
+    function finalRate() public view returns (uint256) {
+        return _finalRate;
+    }
+
+    /**
+     * @dev Returns the rate of tokens per wei at the present time.
+     * Note that, as price _increases_ with time, the rate _decreases_.
+     * @return The number of tokens a buyer gets per wei at a given time
+     */
+    function getCurrentRate() public view returns (uint256) {
+        if (!isOpen()) {
+            return 0;
+        }
+
+        // solhint-disable-next-line not-rely-on-time
+        uint256 elapsedTime = block.timestamp.sub(openingTime());
+        uint256 timeRange = closingTime().sub(openingTime());
+        uint256 rateRange = _initialRate.sub(_finalRate);
+        return _initialRate.sub(elapsedTime.mul(rateRange).div(timeRange));
+    }
+
+    /**
+     * @dev Overrides parent method taking into account variable rate.
+     * @param weiAmount The value in wei to be converted into tokens
+     * @return The number of tokens _weiAmount wei will buy at present time
+     */
+    function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
+        uint256 currentRate = getCurrentRate();
+        return currentRate.mul(weiAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/validation/CappedCrowdsale.sol

@@ -0,0 +1,53 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../../math/SafeMath.sol";
+import "../Crowdsale.sol";
+
+/**
+ * @title CappedCrowdsale
+ * @dev Crowdsale with a limit for total contributions.
+ */
+contract CappedCrowdsale is Initializable, Crowdsale {
+    using SafeMath for uint256;
+
+    uint256 private _cap;
+
+    /**
+     * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
+     * @param cap Max amount of wei to be contributed
+     */
+    function initialize(uint256 cap) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
+
+        require(cap > 0);
+        _cap = cap;
+    }
+
+    /**
+     * @return the cap of the crowdsale.
+     */
+    function cap() public view returns (uint256) {
+        return _cap;
+    }
+
+    /**
+     * @dev Checks whether the cap has been reached.
+     * @return Whether the cap was reached
+     */
+    function capReached() public view returns (bool) {
+        return weiRaised() >= _cap;
+    }
+
+    /**
+     * @dev Extend parent behavior requiring purchase to respect the funding cap.
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        super._preValidatePurchase(beneficiary, weiAmount);
+        require(weiRaised().add(weiAmount) <= _cap);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol

@@ -0,0 +1,72 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../../math/SafeMath.sol";
+import "../Crowdsale.sol";
+import "../../access/roles/CapperRole.sol";
+
+/**
+ * @title IndividuallyCappedCrowdsale
+ * @dev Crowdsale with per-beneficiary caps.
+ */
+contract IndividuallyCappedCrowdsale is Initializable, Crowdsale, CapperRole {
+    using SafeMath for uint256;
+
+    mapping(address => uint256) private _contributions;
+    mapping(address => uint256) private _caps;
+
+    function initialize(address sender) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
+
+        CapperRole.initialize(sender);
+    }
+
+    /**
+     * @dev Sets a specific beneficiary's maximum contribution.
+     * @param beneficiary Address to be capped
+     * @param cap Wei limit for individual contribution
+     */
+    function setCap(address beneficiary, uint256 cap) external onlyCapper {
+        _caps[beneficiary] = cap;
+    }
+
+    /**
+     * @dev Returns the cap of a specific beneficiary.
+     * @param beneficiary Address whose cap is to be checked
+     * @return Current cap for individual beneficiary
+     */
+    function getCap(address beneficiary) public view returns (uint256) {
+        return _caps[beneficiary];
+    }
+
+    /**
+     * @dev Returns the amount contributed so far by a specific beneficiary.
+     * @param beneficiary Address of contributor
+     * @return Beneficiary contribution so far
+     */
+    function getContribution(address beneficiary) public view returns (uint256) {
+        return _contributions[beneficiary];
+    }
+
+    /**
+     * @dev Extend parent behavior requiring purchase to respect the beneficiary's funding cap.
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
+        super._preValidatePurchase(beneficiary, weiAmount);
+        require(_contributions[beneficiary].add(weiAmount) <= _caps[beneficiary]);
+    }
+
+    /**
+     * @dev Extend parent behavior to update beneficiary contributions
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
+        super._updatePurchasingState(beneficiary, weiAmount);
+        _contributions[beneficiary] = _contributions[beneficiary].add(weiAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/validation/PausableCrowdsale.sol

@@ -0,0 +1,31 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../Crowdsale.sol";
+import "../../lifecycle/Pausable.sol";
+
+/**
+ * @title PausableCrowdsale
+ * @dev Extension of Crowdsale contract where purchases can be paused and unpaused by the pauser role.
+ */
+contract PausableCrowdsale is Initializable, Crowdsale, Pausable {
+    function initialize(address sender) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
+
+        Pausable.initialize(sender);
+    }
+
+    /**
+     * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
+     * Use super to concatenate validations.
+     * Adds the validation that the crowdsale must not be paused.
+     * @param _beneficiary Address performing the token purchase
+     * @param _weiAmount Value in wei involved in the purchase
+     */
+    function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal view whenNotPaused {
+        return super._preValidatePurchase(_beneficiary, _weiAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/validation/TimedCrowdsale.sol

@@ -0,0 +1,105 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../../math/SafeMath.sol";
+import "../Crowdsale.sol";
+
+/**
+ * @title TimedCrowdsale
+ * @dev Crowdsale accepting contributions only within a time frame.
+ */
+contract TimedCrowdsale is Initializable, Crowdsale {
+    using SafeMath for uint256;
+
+    uint256 private _openingTime;
+    uint256 private _closingTime;
+
+    /**
+     * Event for crowdsale extending
+     * @param newClosingTime new closing time
+     * @param prevClosingTime old closing time
+     */
+    event TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime);
+
+    /**
+     * @dev Reverts if not in crowdsale time range.
+     */
+    modifier onlyWhileOpen {
+        require(isOpen());
+        _;
+    }
+
+    /**
+     * @dev Constructor, takes crowdsale opening and closing times.
+     * @param openingTime Crowdsale opening time
+     * @param closingTime Crowdsale closing time
+     */
+    function initialize(uint256 openingTime, uint256 closingTime) public initializer {
+        assert(Crowdsale._hasBeenInitialized());
+
+        // solhint-disable-next-line not-rely-on-time
+        require(openingTime >= block.timestamp);
+        require(closingTime > openingTime);
+
+        _openingTime = openingTime;
+        _closingTime = closingTime;
+    }
+
+    /**
+     * @return the crowdsale opening time.
+     */
+    function openingTime() public view returns (uint256) {
+        return _openingTime;
+    }
+
+    /**
+     * @return the crowdsale closing time.
+     */
+    function closingTime() public view returns (uint256) {
+        return _closingTime;
+    }
+
+    /**
+     * @return true if the crowdsale is open, false otherwise.
+     */
+    function isOpen() public view returns (bool) {
+        // solhint-disable-next-line not-rely-on-time
+        return block.timestamp >= _openingTime && block.timestamp <= _closingTime;
+    }
+
+    /**
+     * @dev Checks whether the period in which the crowdsale is open has already elapsed.
+     * @return Whether crowdsale period has elapsed
+     */
+    function hasClosed() public view returns (bool) {
+        // solhint-disable-next-line not-rely-on-time
+        return block.timestamp > _closingTime;
+    }
+
+    function _hasBeenInitialized() internal view returns (bool) {
+        return ((_openingTime > 0) && (_closingTime > 0));
+    }
+
+    /**
+     * @dev Extend parent behavior requiring to be within contributing period
+     * @param beneficiary Token purchaser
+     * @param weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal onlyWhileOpen view {
+        super._preValidatePurchase(beneficiary, weiAmount);
+    }
+
+    /**
+     * @dev Extend crowdsale
+     * @param newClosingTime Crowdsale closing time
+     */
+    function _extendTime(uint256 newClosingTime) internal {
+        require(!hasClosed());
+        require(newClosingTime > _closingTime);
+
+        emit TimedCrowdsaleExtended(_closingTime, newClosingTime);
+        _closingTime = newClosingTime;
+    }
+
+    uint256[50] private ______gap;
+}

contracts/crowdsale/validation/WhitelistCrowdsale.sol

@@ -0,0 +1,29 @@
+pragma solidity ^0.5.2;
+import "../Crowdsale.sol";
+import "../../access/roles/WhitelistedRole.sol";
+
+
+/**
+ * @title WhitelistCrowdsale
+ * @dev Crowdsale in which only whitelisted users can contribute.
+ */
+contract WhitelistCrowdsale is Initializable, WhitelistedRole, Crowdsale {
+    function initialize(address sender) public initializer {
+        WhitelistedRole.initialize(sender);
+
+        assert(Crowdsale._hasBeenInitialized());
+    }
+
+    /**
+     * @dev Extend parent behavior requiring beneficiary to be whitelisted. Note that no
+     * restriction is imposed on the account sending the transaction.
+     * @param _beneficiary Token beneficiary
+     * @param _weiAmount Amount of wei contributed
+     */
+    function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal view {
+        require(isWhitelisted(_beneficiary));
+        super._preValidatePurchase(_beneficiary, _weiAmount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/cryptography/ECDSA.sol

@@ -0,0 +1,67 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title Elliptic curve signature operations
+ * @dev Based on https://gist.github.com/axic/5b33912c6f61ae6fd96d6c4a47afde6d
+ * TODO Remove this library once solidity supports passing a signature to ecrecover.
+ * See https://github.com/ethereum/solidity/issues/864
+ */
+
+library ECDSA {
+    /**
+     * @dev Recover signer address from a message by using their signature
+     * @param hash bytes32 message, the hash is the signed message. What is recovered is the signer address.
+     * @param signature bytes signature, the signature is generated using web3.eth.sign()
+     */
+    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
+        // Check the signature length
+        if (signature.length != 65) {
+            return (address(0));
+        }
+
+        // Divide the signature in r, s and v variables
+        bytes32 r;
+        bytes32 s;
+        uint8 v;
+
+        // ecrecover takes the signature parameters, and the only way to get them
+        // currently is to use assembly.
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            r := mload(add(signature, 0x20))
+            s := mload(add(signature, 0x40))
+            v := byte(0, mload(add(signature, 0x60)))
+        }
+
+        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
+        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
+        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
+        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
+        //
+        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
+        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
+        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
+        // these malleable signatures as well.
+        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
+            return address(0);
+        }
+
+        if (v != 27 && v != 28) {
+            return address(0);
+        }
+
+        // If the signature is valid (and not malleable), return the signer address
+        return ecrecover(hash, v, r, s);
+    }
+
+    /**
+     * toEthSignedMessageHash
+     * @dev prefix a bytes32 value with "\x19Ethereum Signed Message:"
+     * and hash the result
+     */
+    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
+        // 32 is the length in bytes of hash,
+        // enforced by the type signature above
+        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
+    }
+}

contracts/cryptography/MerkleProof.sol

@@ -0,0 +1,34 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title MerkleProof
+ * @dev Merkle proof verification based on
+ * https://github.com/ameensol/merkle-tree-solidity/blob/master/src/MerkleProof.sol
+ */
+library MerkleProof {
+    /**
+     * @dev Verifies a Merkle proof proving the existence of a leaf in a Merkle tree. Assumes that each pair of leaves
+     * and each pair of pre-images are sorted.
+     * @param proof Merkle proof containing sibling hashes on the branch from the leaf to the root of the Merkle tree
+     * @param root Merkle root
+     * @param leaf Leaf of Merkle tree
+     */
+    function verify(bytes32[] memory proof, bytes32 root, bytes32 leaf) internal pure returns (bool) {
+        bytes32 computedHash = leaf;
+
+        for (uint256 i = 0; i < proof.length; i++) {
+            bytes32 proofElement = proof[i];
+
+            if (computedHash < proofElement) {
+                // Hash(current computed hash + current element of the proof)
+                computedHash = keccak256(abi.encodePacked(computedHash, proofElement));
+            } else {
+                // Hash(current element of the proof + current computed hash)
+                computedHash = keccak256(abi.encodePacked(proofElement, computedHash));
+            }
+        }
+
+        // Check if the computed hash (root) is equal to the provided root
+        return computedHash == root;
+    }
+}

contracts/drafts/Counters.sol

@@ -0,0 +1,37 @@
+pragma solidity ^0.5.2;
+
+import "../math/SafeMath.sol";
+
+/**
+ * @title Counters
+ * @author Matt Condon (@shrugs)
+ * @dev Provides counters that can only be incremented or decremented by one. This can be used e.g. to track the number
+ * of elements in a mapping, issuing ERC721 ids, or counting request ids
+ *
+ * Include with `using Counters for Counters.Counter;`
+ * Since it is not possible to overflow a 256 bit integer with increments of one, `increment` can skip the SafeMath
+ * overflow check, thereby saving gas. This does assume however correct usage, in that the underlying `_value` is never
+ * directly accessed.
+ */
+library Counters {
+    using SafeMath for uint256;
+
+    struct Counter {
+        // This variable should never be directly accessed by users of the library: interactions must be restricted to
+        // the library's function. As of Solidity v0.5.2, this cannot be enforced, though there is a proposal to add
+        // this feature: see https://github.com/ethereum/solidity/issues/4637
+        uint256 _value; // default: 0
+    }
+
+    function current(Counter storage counter) internal view returns (uint256) {
+        return counter._value;
+    }
+
+    function increment(Counter storage counter) internal {
+        counter._value += 1;
+    }
+
+    function decrement(Counter storage counter) internal {
+        counter._value = counter._value.sub(1);
+    }
+}

contracts/drafts/ERC1046/ERC20Metadata.sol

@@ -0,0 +1,27 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../../token/ERC20/IERC20.sol";
+
+/**
+ * @title ERC-1047 Token Metadata
+ * @dev See https://eips.ethereum.org/EIPS/eip-1046
+ * @dev tokenURI must respond with a URI that implements https://eips.ethereum.org/EIPS/eip-1047
+ */
+contract ERC20Metadata is Initializable {
+    string private _tokenURI;
+
+    function initialize(string memory tokenURI_) public {
+        _setTokenURI(tokenURI_);
+    }
+
+    function tokenURI() external view returns (string memory) {
+        return _tokenURI;
+    }
+
+    function _setTokenURI(string memory tokenURI_) internal {
+        _tokenURI = tokenURI_;
+    }
+
+    uint256[50] private ______gap;
+}

contracts/drafts/ERC20Migrator.sol

@@ -0,0 +1,104 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../token/ERC20/IERC20.sol";
+import "../token/ERC20/ERC20Mintable.sol";
+import "../token/ERC20/SafeERC20.sol";
+import "../math/Math.sol";
+
+/**
+ * @title ERC20Migrator
+ * @dev This contract can be used to migrate an ERC20 token from one
+ * contract to another, where each token holder has to opt-in to the migration.
+ * To opt-in, users must approve for this contract the number of tokens they
+ * want to migrate. Once the allowance is set up, anyone can trigger the
+ * migration to the new token contract. In this way, token holders "turn in"
+ * their old balance and will be minted an equal amount in the new token.
+ * The new token contract must be mintable. For the precise interface refer to
+ * OpenZeppelin's ERC20Mintable, but the only functions that are needed are
+ * `isMinter(address)` and `mint(address, amount)`. The migrator will check
+ * that it is a minter for the token.
+ * The balance from the legacy token will be transferred to the migrator, as it
+ * is migrated, and remain there forever.
+ * Although this contract can be used in many different scenarios, the main
+ * motivation was to provide a way to migrate ERC20 tokens into an upgradeable
+ * version of it using the OpenZeppelin SDK. To read more about how this can be done
+ * using this implementation, please follow the official documentation site of
+ * the OpenZeppelinSDK: https://docs.zeppelinos.org/docs/erc20_onboarding.html
+ * Example of usage:
+ * ```
+ * const migrator = await ERC20Migrator.new(legacyToken.address);
+ * await newToken.addMinter(migrator.address);
+ * await migrator.beginMigration(newToken.address);
+ * ```
+ */
+contract ERC20Migrator is Initializable {
+    using SafeERC20 for IERC20;
+
+    /// Address of the old token contract
+    IERC20 private _legacyToken;
+
+    /// Address of the new token contract
+    ERC20Mintable private _newToken;
+
+    /**
+     * @param legacyToken address of the old token contract
+     */
+    function initialize(IERC20 legacyToken) public initializer {
+        require(address(legacyToken) != address(0));
+        _legacyToken = legacyToken;
+    }
+
+    /**
+     * @dev Returns the legacy token that is being migrated.
+     */
+    function legacyToken() public view returns (IERC20) {
+        return _legacyToken;
+    }
+
+    /**
+     * @dev Returns the new token to which we are migrating.
+     */
+    function newToken() public view returns (IERC20) {
+        return _newToken;
+    }
+
+    /**
+     * @dev Begins the migration by setting which is the new token that will be
+     * minted. This contract must be a minter for the new token.
+     * @param newToken_ the token that will be minted
+     */
+    function beginMigration(ERC20Mintable newToken_) public {
+        require(address(_newToken) == address(0));
+        require(address(newToken_) != address(0));
+        require(newToken_.isMinter(address(this)));
+
+        _newToken = newToken_;
+    }
+
+    /**
+     * @dev Transfers part of an account's balance in the old token to this
+     * contract, and mints the same amount of new tokens for that account.
+     * @param account whose tokens will be migrated
+     * @param amount amount of tokens to be migrated
+     */
+    function migrate(address account, uint256 amount) public {
+        require(address(_newToken) != address(0));
+        _legacyToken.safeTransferFrom(account, address(this), amount);
+        _newToken.mint(account, amount);
+    }
+
+    /**
+     * @dev Transfers all of an account's allowed balance in the old token to
+     * this contract, and mints the same amount of new tokens for that account.
+     * @param account whose tokens will be migrated
+     */
+    function migrateAll(address account) public {
+        uint256 balance = _legacyToken.balanceOf(account);
+        uint256 allowance = _legacyToken.allowance(account, address(this));
+        uint256 amount = Math.min(balance, allowance);
+        migrate(account, amount);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/drafts/ERC20Snapshot.sol

@@ -0,0 +1,142 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../math/SafeMath.sol";
+import "../utils/Arrays.sol";
+import "../drafts/Counters.sol";
+import "../token/ERC20/ERC20.sol";
+
+/**
+ * @title ERC20 token with snapshots.
+ * @dev Inspired by Jordi Baylina's MiniMeToken to record historical balances:
+ * https://github.com/Giveth/minime/blob/ea04d950eea153a04c51fa510b068b9dded390cb/contracts/MiniMeToken.sol
+ * When a snapshot is made, the balances and totalSupply at the time of the snapshot are recorded for later
+ * access.
+ *
+ * To make a snapshot, call the `snapshot` function, which will emit the `Snapshot` event and return a snapshot id.
+ * To get the total supply from a snapshot, call the function `totalSupplyAt` with the snapshot id.
+ * To get the balance of an account from a snapshot, call the `balanceOfAt` function with the snapshot id and the
+ * account address.
+ * @author Validity Labs AG <info@validitylabs.org>
+ */
+contract ERC20Snapshot is Initializable, ERC20 {
+    using SafeMath for uint256;
+    using Arrays for uint256[];
+    using Counters for Counters.Counter;
+
+    // Snapshotted values have arrays of ids and the value corresponding to that id. These could be an array of a
+    // Snapshot struct, but that would impede usage of functions that work on an array.
+    struct Snapshots {
+        uint256[] ids;
+        uint256[] values;
+    }
+
+    mapping (address => Snapshots) private _accountBalanceSnapshots;
+    Snapshots private _totalSupplySnaphots;
+
+    // Snapshot ids increase monotonically, with the first value being 1. An id of 0 is invalid.
+    Counters.Counter private _currentSnapshotId;
+
+    event Snapshot(uint256 id);
+
+    // Creates a new snapshot id. Balances are only stored in snapshots on demand: unless a snapshot was taken, a
+    // balance change will not be recorded. This means the extra added cost of storing snapshotted balances is only paid
+    // when required, but is also flexible enough that it allows for e.g. daily snapshots.
+    function snapshot() public returns (uint256) {
+        _currentSnapshotId.increment();
+
+        uint256 currentId = _currentSnapshotId.current();
+        emit Snapshot(currentId);
+        return currentId;
+    }
+
+    function balanceOfAt(address account, uint256 snapshotId) public view returns (uint256) {
+        (bool snapshotted, uint256 value) = _valueAt(snapshotId, _accountBalanceSnapshots[account]);
+
+        return snapshotted ? value : balanceOf(account);
+    }
+
+    function totalSupplyAt(uint256 snapshotId) public view returns(uint256) {
+        (bool snapshotted, uint256 value) = _valueAt(snapshotId, _totalSupplySnaphots);
+
+        return snapshotted ? value : totalSupply();
+    }
+
+    // _transfer, _mint and _burn are the only functions where the balances are modified, so it is there that the
+    // snapshots are updated. Note that the update happens _before_ the balance change, with the pre-modified value.
+    // The same is true for the total supply and _mint and _burn.
+    function _transfer(address from, address to, uint256 value) internal {
+        _updateAccountSnapshot(from);
+        _updateAccountSnapshot(to);
+
+        super._transfer(from, to, value);
+    }
+
+    function _mint(address account, uint256 value) internal {
+        _updateAccountSnapshot(account);
+        _updateTotalSupplySnapshot();
+
+        super._mint(account, value);
+    }
+
+    function _burn(address account, uint256 value) internal {
+        _updateAccountSnapshot(account);
+        _updateTotalSupplySnapshot();
+
+        super._burn(account, value);
+    }
+
+    // When a valid snapshot is queried, there are three possibilities:
+    //  a) The queried value was not modified after the snapshot was taken. Therefore, a snapshot entry was never
+    //  created for this id, and all stored snapshot ids are smaller than the requested one. The value that corresponds
+    //  to this id is the current one.
+    //  b) The queried value was modified after the snapshot was taken. Therefore, there will be an entry with the
+    //  requested id, and its value is the one to return.
+    //  c) More snapshots were created after the requested one, and the queried value was later modified. There will be
+    //  no entry for the requested id: the value that corresponds to it is that of the smallest snapshot id that is
+    //  larger than the requested one.
+    //
+    // In summary, we need to find an element in an array, returning the index of the smallest value that is larger if
+    // it is not found, unless said value doesn't exist (e.g. when all values are smaller). Arrays.findUpperBound does
+    // exactly this.
+    function _valueAt(uint256 snapshotId, Snapshots storage snapshots)
+        private view returns (bool, uint256)
+    {
+        require(snapshotId > 0);
+        require(snapshotId <= _currentSnapshotId.current());
+
+        uint256 index = snapshots.ids.findUpperBound(snapshotId);
+
+        if (index == snapshots.ids.length) {
+            return (false, 0);
+        } else {
+            return (true, snapshots.values[index]);
+        }
+    }
+
+    function _updateAccountSnapshot(address account) private {
+        _updateSnapshot(_accountBalanceSnapshots[account], balanceOf(account));
+    }
+
+    function _updateTotalSupplySnapshot() private {
+        _updateSnapshot(_totalSupplySnaphots, totalSupply());
+    }
+
+    function _updateSnapshot(Snapshots storage snapshots, uint256 currentValue) private {
+        uint256 currentId = _currentSnapshotId.current();
+        if (_lastSnapshotId(snapshots.ids) < currentId) {
+            snapshots.ids.push(currentId);
+            snapshots.values.push(currentValue);
+        }
+    }
+
+    function _lastSnapshotId(uint256[] storage ids) private view returns (uint256) {
+        if (ids.length == 0) {
+            return 0;
+        } else {
+            return ids[ids.length - 1];
+        }
+    }
+
+    uint256[50] private ______gap;
+}

contracts/drafts/SignatureBouncer.sol

@@ -0,0 +1,129 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../GSN/Context.sol";
+import "../access/roles/SignerRole.sol";
+import "../cryptography/ECDSA.sol";
+
+/**
+ * @title SignatureBouncer
+ * @author PhABC, Shrugs and aflesher
+ * @dev SignatureBouncer allows users to submit a signature as a permission to
+ * do an action.
+ * If the signature is from one of the authorized signer addresses, the
+ * signature is valid.
+ * Note that SignatureBouncer offers no protection against replay attacks, users
+ * must add this themselves!
+ *
+ * Signer addresses can be individual servers signing grants or different
+ * users within a decentralized club that have permission to invite other
+ * members. This technique is useful for whitelists and airdrops; instead of
+ * putting all valid addresses on-chain, simply sign a grant of the form
+ * keccak256(abi.encodePacked(`:contractAddress` + `:granteeAddress`)) using a
+ * valid signer address.
+ * Then restrict access to your crowdsale/whitelist/airdrop using the
+ * `onlyValidSignature` modifier (or implement your own using _isValidSignature).
+ * In addition to `onlyValidSignature`, `onlyValidSignatureAndMethod` and
+ * `onlyValidSignatureAndData` can be used to restrict access to only a given
+ * method or a given method with given parameters respectively.
+ * See the tests in SignatureBouncer.test.js for specific usage examples.
+ *
+ * @notice A method that uses the `onlyValidSignatureAndData` modifier must make
+ * the _signature parameter the "last" parameter. You cannot sign a message that
+ * has its own signature in it so the last 128 bytes of msg.data (which
+ * represents the length of the _signature data and the _signature data itself)
+ * is ignored when validating. Also non fixed sized parameters make constructing
+ * the data in the signature much more complex.
+ * See https://ethereum.stackexchange.com/a/50616 for more details.
+ */
+contract SignatureBouncer is Initializable, Context, SignerRole {
+    using ECDSA for bytes32;
+
+    // Function selectors are 4 bytes long, as documented in
+    // https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector
+    uint256 private constant _METHOD_ID_SIZE = 4;
+    // Signature size is 65 bytes (tightly packed v + r + s), but gets padded to 96 bytes
+    uint256 private constant _SIGNATURE_SIZE = 96;
+
+    function initialize(address sender) public initializer {
+        SignerRole.initialize(sender);
+    }
+
+    /**
+     * @dev requires that a valid signature of a signer was provided
+     */
+    modifier onlyValidSignature(bytes memory signature) {
+        require(_isValidSignature(_msgSender(), signature), "SignatureBouncer: invalid signature for caller");
+        _;
+    }
+
+    /**
+     * @dev requires that a valid signature with a specified method of a signer was provided
+     */
+    modifier onlyValidSignatureAndMethod(bytes memory signature) {
+        // solhint-disable-next-line max-line-length
+        require(_isValidSignatureAndMethod(_msgSender(), signature), "SignatureBouncer: invalid signature for caller and method");
+        _;
+    }
+
+    /**
+     * @dev requires that a valid signature with a specified method and params of a signer was provided
+     */
+    modifier onlyValidSignatureAndData(bytes memory signature) {
+        // solhint-disable-next-line max-line-length
+        require(_isValidSignatureAndData(_msgSender(), signature), "SignatureBouncer: invalid signature for caller and data");
+        _;
+    }
+
+    /**
+     * @dev is the signature of `this + account` from a signer?
+     * @return bool
+     */
+    function _isValidSignature(address account, bytes memory signature) internal view returns (bool) {
+        return _isValidDataHash(keccak256(abi.encodePacked(address(this), account)), signature);
+    }
+
+    /**
+     * @dev is the signature of `this + account + methodId` from a signer?
+     * @return bool
+     */
+    function _isValidSignatureAndMethod(address account, bytes memory signature) internal view returns (bool) {
+        bytes memory msgData = _msgData();
+        bytes memory data = new bytes(_METHOD_ID_SIZE);
+        for (uint256 i = 0; i < data.length; i++) {
+            data[i] = msgData[i];
+        }
+        return _isValidDataHash(keccak256(abi.encodePacked(address(this), account, data)), signature);
+    }
+
+    /**
+     * @dev is the signature of `this + account + methodId + params(s)` from a signer?
+     * @notice the signature parameter of the method being validated must be the "last" parameter
+     * @return bool
+     */
+    function _isValidSignatureAndData(address account, bytes memory signature) internal view returns (bool) {
+        bytes memory msgData = _msgData();
+        require(msgData.length > _SIGNATURE_SIZE, "SignatureBouncer: data is too short");
+
+        bytes memory data = new bytes(msgData.length - _SIGNATURE_SIZE);
+        for (uint256 i = 0; i < data.length; i++) {
+            data[i] = msgData[i];
+        }
+
+        return _isValidDataHash(keccak256(abi.encodePacked(address(this), account, data)), signature);
+    }
+
+    /**
+     * @dev internal function to convert a hash to an eth signed message
+     * and then recover the signature and check it against the signer role
+     * @return bool
+     */
+    function _isValidDataHash(bytes32 hash, bytes memory signature) internal view returns (bool) {
+        address signer = hash.toEthSignedMessageHash().recover(signature);
+
+        return signer != address(0) && isSigner(signer);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/drafts/SignedSafeMath.sol

@@ -0,0 +1,60 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title SignedSafeMath
+ * @dev Signed math operations with safety checks that revert on error
+ */
+library SignedSafeMath {
+    int256 constant private INT256_MIN = -2**255;
+
+    /**
+     * @dev Multiplies two signed integers, reverts on overflow.
+     */
+    function mul(int256 a, int256 b) internal pure returns (int256) {
+        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+        // benefit is lost if 'b' is also tested.
+        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
+        if (a == 0) {
+            return 0;
+        }
+
+        require(!(a == -1 && b == INT256_MIN)); // This is the only case of overflow not detected by the check below
+
+        int256 c = a * b;
+        require(c / a == b);
+
+        return c;
+    }
+
+    /**
+     * @dev Integer division of two signed integers truncating the quotient, reverts on division by zero.
+     */
+    function div(int256 a, int256 b) internal pure returns (int256) {
+        require(b != 0); // Solidity only automatically asserts when dividing by 0
+        require(!(b == -1 && a == INT256_MIN)); // This is the only case of overflow
+
+        int256 c = a / b;
+
+        return c;
+    }
+
+    /**
+     * @dev Subtracts two signed integers, reverts on overflow.
+     */
+    function sub(int256 a, int256 b) internal pure returns (int256) {
+        int256 c = a - b;
+        require((b >= 0 && c <= a) || (b < 0 && c > a));
+
+        return c;
+    }
+
+    /**
+     * @dev Adds two signed integers, reverts on overflow.
+     */
+    function add(int256 a, int256 b) internal pure returns (int256) {
+        int256 c = a + b;
+        require((b >= 0 && c >= a) || (b < 0 && c < a));
+
+        return c;
+    }
+}

contracts/drafts/TokenVesting.sol

@@ -0,0 +1,177 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../token/ERC20/SafeERC20.sol";
+import "../ownership/Ownable.sol";
+import "../math/SafeMath.sol";
+
+/**
+ * @title TokenVesting
+ * @dev A token holder contract that can release its token balance gradually like a
+ * typical vesting scheme, with a cliff and vesting period. Optionally revocable by the
+ * owner.
+ */
+contract TokenVesting is Initializable, Ownable {
+    // The vesting schedule is time-based (i.e. using block timestamps as opposed to e.g. block numbers), and is
+    // therefore sensitive to timestamp manipulation (which is something miners can do, to a certain degree). Therefore,
+    // it is recommended to avoid using short time durations (less than a minute). Typical vesting schemes, with a
+    // cliff period of a year and a duration of four years, are safe to use.
+    // solhint-disable not-rely-on-time
+
+    using SafeMath for uint256;
+    using SafeERC20 for IERC20;
+
+    event TokensReleased(address token, uint256 amount);
+    event TokenVestingRevoked(address token);
+
+    // beneficiary of tokens after they are released
+    address private _beneficiary;
+
+    // Durations and timestamps are expressed in UNIX time, the same units as block.timestamp.
+    uint256 private _cliff;
+    uint256 private _start;
+    uint256 private _duration;
+
+    bool private _revocable;
+
+    mapping (address => uint256) private _released;
+    mapping (address => bool) private _revoked;
+
+    /**
+     * @dev Creates a vesting contract that vests its balance of any ERC20 token to the
+     * beneficiary, gradually in a linear fashion until start + duration. By then all
+     * of the balance will have vested.
+     * @param beneficiary address of the beneficiary to whom vested tokens are transferred
+     * @param cliffDuration duration in seconds of the cliff in which tokens will begin to vest
+     * @param start the time (as Unix time) at which point vesting starts
+     * @param duration duration in seconds of the period in which the tokens will vest
+     * @param revocable whether the vesting is revocable or not
+     */
+    function initialize(address beneficiary, uint256 start, uint256 cliffDuration, uint256 duration, bool revocable, address sender) public initializer {
+        Ownable.initialize(sender);
+
+        require(beneficiary != address(0));
+        require(cliffDuration <= duration);
+        require(duration > 0);
+        require(start.add(duration) > block.timestamp);
+
+        _beneficiary = beneficiary;
+        _revocable = revocable;
+        _duration = duration;
+        _cliff = start.add(cliffDuration);
+        _start = start;
+    }
+
+    /**
+     * @return the beneficiary of the tokens.
+     */
+    function beneficiary() public view returns (address) {
+        return _beneficiary;
+    }
+
+    /**
+     * @return the cliff time of the token vesting.
+     */
+    function cliff() public view returns (uint256) {
+        return _cliff;
+    }
+
+    /**
+     * @return the start time of the token vesting.
+     */
+    function start() public view returns (uint256) {
+        return _start;
+    }
+
+    /**
+     * @return the duration of the token vesting.
+     */
+    function duration() public view returns (uint256) {
+        return _duration;
+    }
+
+    /**
+     * @return true if the vesting is revocable.
+     */
+    function revocable() public view returns (bool) {
+        return _revocable;
+    }
+
+    /**
+     * @return the amount of the token released.
+     */
+    function released(address token) public view returns (uint256) {
+        return _released[token];
+    }
+
+    /**
+     * @return true if the token is revoked.
+     */
+    function revoked(address token) public view returns (bool) {
+        return _revoked[token];
+    }
+
+    /**
+     * @notice Transfers vested tokens to beneficiary.
+     * @param token ERC20 token which is being vested
+     */
+    function release(IERC20 token) public {
+        uint256 unreleased = _releasableAmount(token);
+
+        require(unreleased > 0);
+
+        _released[address(token)] = _released[address(token)].add(unreleased);
+
+        token.safeTransfer(_beneficiary, unreleased);
+
+        emit TokensReleased(address(token), unreleased);
+    }
+
+    /**
+     * @notice Allows the owner to revoke the vesting. Tokens already vested
+     * remain in the contract, the rest are returned to the owner.
+     * @param token ERC20 token which is being vested
+     */
+    function revoke(IERC20 token) public onlyOwner {
+        require(_revocable);
+        require(!_revoked[address(token)]);
+
+        uint256 balance = token.balanceOf(address(this));
+
+        uint256 unreleased = _releasableAmount(token);
+        uint256 refund = balance.sub(unreleased);
+
+        _revoked[address(token)] = true;
+
+        token.safeTransfer(owner(), refund);
+
+        emit TokenVestingRevoked(address(token));
+    }
+
+    /**
+     * @dev Calculates the amount that has already vested but hasn't been released yet.
+     * @param token ERC20 token which is being vested
+     */
+    function _releasableAmount(IERC20 token) private view returns (uint256) {
+        return _vestedAmount(token).sub(_released[address(token)]);
+    }
+
+    /**
+     * @dev Calculates the amount that has already vested.
+     * @param token ERC20 token which is being vested
+     */
+    function _vestedAmount(IERC20 token) private view returns (uint256) {
+        uint256 currentBalance = token.balanceOf(address(this));
+        uint256 totalBalance = currentBalance.add(_released[address(token)]);
+
+        if (block.timestamp < _cliff) {
+            return 0;
+        } else if (block.timestamp >= _start.add(_duration) || _revoked[address(token)]) {
+            return totalBalance;
+        } else {
+            return totalBalance.mul(block.timestamp.sub(_start)).div(_duration);
+        }
+    }
+
+    uint256[50] private ______gap;
+}

contracts/examples/BadArrayUse.sol

@@ -1,23 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import '../PullPayment.sol';
-
-
-// UNSAFE CODE, DO NOT USE!
-contract BadArrayUse is PullPayment {
-  address[] employees;
-
-  function payBonus() {
-    for (var i = 0; i < employees.length; i++) {
-			address employee = employees[i];
-			uint bonus = calculateBonus(employee);
-    	asyncSend(employee, bonus);
-    }
-  }
-
-	function calculateBonus(address employee) returns (uint) {
-    // some expensive computation...
-  }
-
-}

contracts/examples/BadFailEarly.sol

@@ -1,17 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-// UNSAFE CODE, DO NOT USE!
-contract BadFailEarly {
-
-  uint constant DEFAULT_SALARY = 50000;
-  mapping(string => uint) nameToSalary;
-
-  function getSalary(string name) constant returns (uint) {
-    if (bytes(name).length != 0 && nameToSalary[name] != 0) {
-      return nameToSalary[name];
-    } else {
-      return DEFAULT_SALARY;
-    }
-  }
-}

contracts/examples/BadPushPayments.sol

@@ -1,23 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-// UNSAFE CODE, DO NOT USE!
-contract BadPushPayments {
-
-	address highestBidder;
-	uint highestBid;
-
-	function bid() payable {
-		if (msg.value < highestBid) throw;
-
-		if (highestBidder != 0) {
-      // return bid to previous winner
-			if (!highestBidder.send(highestBid)) {
-        throw;
-      }
-		}
-
-	  highestBidder = msg.sender;
-	  highestBid = msg.value;
-	}
-}

contracts/examples/GoodArrayUse.sol

@@ -1,25 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import '../PullPayment.sol';
-
-
-contract GoodArrayUse is PullPayment {
-  address[] employees;
-  mapping(address => uint) bonuses;
-
-  function payBonus() {
-    for (uint i = 0; i < employees.length; i++) {
-			address employee = employees[i];
-			uint bonus = bonuses[employee];
-    	asyncSend(employee, bonus);
-    }
-  }
-
-	function calculateBonus(address employee) returns (uint) {
-    uint bonus = 0;
-    // some expensive computation...
-    bonuses[employee] = bonus;
-  }
-
-}

contracts/examples/GoodFailEarly.sol

@@ -1,15 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-contract GoodFailEarly {
-
-  uint constant DEFAULT_SALARY = 50000;
-  mapping(string => uint) nameToSalary;
-
-  function getSalary(string name) constant returns (uint) {
-    if (bytes(name).length == 0) throw;
-    if (nameToSalary[name] == 0) throw;
-
-    return nameToSalary[name];
-  }
-}

contracts/examples/GoodPullPayments.sol

@@ -1,27 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-contract GoodPullPayments {
-  address highestBidder;
-  uint highestBid;
-  mapping(address => uint) refunds;
-
-  function bid() external payable {
-    if (msg.value < highestBid) throw;
-
-    if (highestBidder != 0) {
-      refunds[highestBidder] += highestBid;
-    }
-
-    highestBidder = msg.sender;
-    highestBid = msg.value;
-  }
-
-  function withdrawBid() external {
-    uint refund = refunds[msg.sender];
-    refunds[msg.sender] = 0;
-    if (!msg.sender.send(refund)) {
-      refunds[msg.sender] = refund;
-    }
-  }
-}

contracts/examples/ProofOfExistence.sol

@@ -1,38 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-/*
- * Proof of Existence example contract
- * see https://medium.com/zeppelin-blog/the-hitchhikers-guide-to-smart-contracts-in-ethereum-848f08001f05
- */
-contract ProofOfExistence {
-
-  mapping (bytes32 => bool) public proofs;
-
-  // store a proof of existence in the contract state
-  function storeProof(bytes32 proof) {
-    proofs[proof] = true;
-  }
-
-  // calculate and store the proof for a document
-  function notarize(string document) {
-    var proof = calculateProof(document);
-    storeProof(proof);
-  }
-
-  // helper function to get a document's sha256
-  function calculateProof(string document) constant returns (bytes32) {
-    return sha256(document);
-  }
-
-  // check if a document has been notarized
-  function checkDocument(string document) constant returns (bool) {
-    var proof = calculateProof(document);
-    return hasProof(proof);
-  }
-
-  // returns true if proof is stored
-  function hasProof(bytes32 proof) constant returns (bool) {
-    return proofs[proof];
-  }
-}

contracts/examples/PullPaymentBid.sol

@@ -1,20 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import '../PullPayment.sol';
-
-
-contract PullPaymentBid is PullPayment {
-  address public highestBidder;
-  uint public highestBid;
-  
-  function bid() external payable {
-    if (msg.value <= highestBid) throw;
-    
-    if (highestBidder != 0) {
-      asyncSend(highestBidder, highestBid);
-    }
-    highestBidder = msg.sender;
-    highestBid = msg.value;
-  }
-}

contracts/examples/SampleCrowdsale.sol

@@ -0,0 +1,62 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "../crowdsale/validation/CappedCrowdsale.sol";
+import "../crowdsale/distribution/RefundableCrowdsale.sol";
+import "../crowdsale/emission/MintedCrowdsale.sol";
+import "../token/ERC20/ERC20Mintable.sol";
+import "../token/ERC20/ERC20Detailed.sol";
+
+/**
+ * @title SampleCrowdsaleToken
+ * @dev Very simple ERC20 Token that can be minted.
+ * It is meant to be used in a crowdsale contract.
+ */
+contract SampleCrowdsaleToken is Initializable, ERC20Mintable, ERC20Detailed {
+    function initialize(address sender) public initializer {
+        ERC20Mintable.initialize(sender);
+        ERC20Detailed.initialize("Sample Crowdsale Token", "SCT", 18);
+    }
+
+    uint256[50] private ______gap;
+}
+
+/**
+ * @title SampleCrowdsale
+ * @dev This is an example of a fully fledged crowdsale.
+ * The way to add new features to a base crowdsale is by multiple inheritance.
+ * In this example we are providing following extensions:
+ * CappedCrowdsale - sets a max boundary for raised funds
+ * RefundableCrowdsale - set a min goal to be reached and returns funds if it's not met
+ * MintedCrowdsale - assumes the token can be minted by the crowdsale, which does so
+ * when receiving purchases.
+ *
+ * After adding multiple features it's good practice to run integration tests
+ * to ensure that subcontracts works together as intended.
+ */
+contract SampleCrowdsale is Initializable, Crowdsale, CappedCrowdsale, RefundableCrowdsale, MintedCrowdsale {
+
+    function initialize(
+        uint256 openingTime,
+        uint256 closingTime,
+        uint256 rate,
+        address payable wallet,
+        uint256 cap,
+        ERC20Mintable token,
+        uint256 goal
+    )
+        public
+        initializer
+    {
+        Crowdsale.initialize(rate, wallet, token);
+        CappedCrowdsale.initialize(cap);
+        TimedCrowdsale.initialize(openingTime, closingTime);
+        RefundableCrowdsale.initialize(goal);
+
+        //As goal needs to be met for a successful crowdsale
+        //the value needs to less or equal than a cap which is limit for accepted funds
+        require(goal <= cap);
+    }
+
+    uint256[50] private ______gap;
+}

contracts/examples/SimpleToken.sol

@@ -0,0 +1,26 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../GSN/Context.sol";
+import "../token/ERC20/ERC20.sol";
+import "../token/ERC20/ERC20Detailed.sol";
+
+/**
+ * @title SimpleToken
+ * @dev Very simple ERC20 Token example, where all tokens are pre-assigned to the creator.
+ * Note they can later distribute these tokens as they wish using `transfer` and other
+ * `ERC20` functions.
+ */
+contract SimpleToken is Initializable, Context,  ERC20, ERC20Detailed {
+
+    /**
+     * @dev Constructor that gives _msgSender() all of existing tokens.
+     */
+    function initialize(address sender) public initializer {
+        ERC20Detailed.initialize("SimpleToken", "SIM", 18);
+        _mint(sender, 10000 * (10 ** uint256(decimals())));
+    }
+
+    uint256[50] private ______gap;
+}

contracts/examples/StoppableBid.sol

@@ -1,26 +0,0 @@
-pragma solidity ^0.4.4;
-
-
-import '../PullPayment.sol';
-import '../Stoppable.sol';
-
-
-contract StoppableBid is Stoppable, PullPayment {
-  address public highestBidder;
-  uint public highestBid;
-
-  function bid() external payable stopInEmergency {
-    if (msg.value <= highestBid) throw;
-    
-    if (highestBidder != 0) {
-      asyncSend(highestBidder, highestBid);
-    }
-    highestBidder = msg.sender;
-    highestBid = msg.value;
-  }
-
-  function withdraw() onlyInEmergency {
-    selfdestruct(owner);
-  }
-
-}

contracts/introspection/ERC165.sol

@@ -0,0 +1,47 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+import "./IERC165.sol";
+
+/**
+ * @title ERC165
+ * @author Matt Condon (@shrugs)
+ * @dev Implements ERC165 using a lookup table.
+ */
+contract ERC165 is Initializable, IERC165 {
+    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
+    /*
+     * 0x01ffc9a7 ===
+     *     bytes4(keccak256('supportsInterface(bytes4)'))
+     */
+
+    /**
+     * @dev a mapping of interface id to whether or not it's supported
+     */
+    mapping(bytes4 => bool) private _supportedInterfaces;
+
+    /**
+     * @dev A contract implementing SupportsInterfaceWithLookup
+     * implement ERC165 itself
+     */
+    function initialize() public initializer {
+        _registerInterface(_INTERFACE_ID_ERC165);
+    }
+
+    /**
+     * @dev implement supportsInterface(bytes4) using a lookup table
+     */
+    function supportsInterface(bytes4 interfaceId) public view returns (bool) {
+        return _supportedInterfaces[interfaceId];
+    }
+
+    /**
+     * @dev internal method for registering an interface
+     */
+    function _registerInterface(bytes4 interfaceId) internal {
+        require(interfaceId != 0xffffffff);
+        _supportedInterfaces[interfaceId] = true;
+    }
+
+    uint256[50] private ______gap;
+}

contracts/introspection/ERC165Checker.sol

@@ -0,0 +1,123 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title ERC165Checker
+ * @dev Use `using ERC165Checker for address`; to include this library
+ * https://eips.ethereum.org/EIPS/eip-165
+ */
+library ERC165Checker {
+    // As per the EIP-165 spec, no interface should ever match 0xffffffff
+    bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;
+
+    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
+    /*
+     * 0x01ffc9a7 ===
+     *     bytes4(keccak256('supportsInterface(bytes4)'))
+     */
+
+    /**
+     * @notice Query if a contract supports ERC165
+     * @param account The address of the contract to query for support of ERC165
+     * @return true if the contract at account implements ERC165
+     */
+    function _supportsERC165(address account) internal view returns (bool) {
+        // Any contract that implements ERC165 must explicitly indicate support of
+        // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
+        return _supportsERC165Interface(account, _INTERFACE_ID_ERC165) &&
+            !_supportsERC165Interface(account, _INTERFACE_ID_INVALID);
+    }
+
+    /**
+     * @notice Query if a contract implements an interface, also checks support of ERC165
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @return true if the contract at account indicates support of the interface with
+     * identifier interfaceId, false otherwise
+     * @dev Interface identification is specified in ERC-165.
+     */
+    function _supportsInterface(address account, bytes4 interfaceId) internal view returns (bool) {
+        // query support of both ERC165 as per the spec and support of _interfaceId
+        return _supportsERC165(account) &&
+            _supportsERC165Interface(account, interfaceId);
+    }
+
+    /**
+     * @notice Query if a contract implements interfaces, also checks support of ERC165
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceIds A list of interface identifiers, as specified in ERC-165
+     * @return true if the contract at account indicates support all interfaces in the
+     * interfaceIds list, false otherwise
+     * @dev Interface identification is specified in ERC-165.
+     */
+    function _supportsAllInterfaces(address account, bytes4[] memory interfaceIds) internal view returns (bool) {
+        // query support of ERC165 itself
+        if (!_supportsERC165(account)) {
+            return false;
+        }
+
+        // query support of each interface in _interfaceIds
+        for (uint256 i = 0; i < interfaceIds.length; i++) {
+            if (!_supportsERC165Interface(account, interfaceIds[i])) {
+                return false;
+            }
+        }
+
+        // all interfaces supported
+        return true;
+    }
+
+    /**
+     * @notice Query if a contract implements an interface, does not check ERC165 support
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @return true if the contract at account indicates support of the interface with
+     * identifier interfaceId, false otherwise
+     * @dev Assumes that account contains a contract that supports ERC165, otherwise
+     * the behavior of this method is undefined. This precondition can be checked
+     * with the `supportsERC165` method in this library.
+     * Interface identification is specified in ERC-165.
+     */
+    function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {
+        // success determines whether the staticcall succeeded and result determines
+        // whether the contract at account indicates support of _interfaceId
+        (bool success, bool result) = _callERC165SupportsInterface(account, interfaceId);
+
+        return (success && result);
+    }
+
+    /**
+     * @notice Calls the function with selector 0x01ffc9a7 (ERC165) and suppresses throw
+     * @param account The address of the contract to query for support of an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @return success true if the STATICCALL succeeded, false otherwise
+     * @return result true if the STATICCALL succeeded and the contract at account
+     * indicates support of the interface with identifier interfaceId, false otherwise
+     */
+    function _callERC165SupportsInterface(address account, bytes4 interfaceId)
+        private
+        view
+        returns (bool success, bool result)
+    {
+        bytes memory encodedParams = abi.encodeWithSelector(_INTERFACE_ID_ERC165, interfaceId);
+
+        // solhint-disable-next-line no-inline-assembly
+        assembly {
+            let encodedParams_data := add(0x20, encodedParams)
+            let encodedParams_size := mload(encodedParams)
+
+            let output := mload(0x40)    // Find empty storage location using "free memory pointer"
+            mstore(output, 0x0)
+
+            success := staticcall(
+                30000,                   // 30k gas
+                account,                 // To addr
+                encodedParams_data,
+                encodedParams_size,
+                output,
+                0x20                     // Outputs are 32 bytes long
+            )
+
+            result := mload(output)      // Load the result
+        }
+    }
+}

contracts/introspection/IERC165.sol

@@ -0,0 +1,15 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title IERC165
+ * @dev https://eips.ethereum.org/EIPS/eip-165
+ */
+interface IERC165 {
+    /**
+     * @notice Query if a contract implements an interface
+     * @param interfaceId The interface identifier, as specified in ERC-165
+     * @dev Interface identification is specified in ERC-165. This function
+     * uses less than 30,000 gas.
+     */
+    function supportsInterface(bytes4 interfaceId) external view returns (bool);
+}

contracts/lifecycle/Pausable.sol

@@ -0,0 +1,64 @@
+pragma solidity ^0.5.2;
+
+import "@openzeppelin/upgrades/contracts/Initializable.sol";
+
+import "../GSN/Context.sol";
+import "../access/roles/PauserRole.sol";
+
+/**
+ * @title Pausable
+ * @dev Base contract which allows children to implement an emergency stop mechanism.
+ */
+contract Pausable is Initializable, Context, PauserRole {
+    event Paused(address account);
+    event Unpaused(address account);
+
+    bool private _paused;
+
+    function initialize(address sender) public initializer {
+        PauserRole.initialize(sender);
+
+        _paused = false;
+    }
+
+    /**
+     * @return true if the contract is paused, false otherwise.
+     */
+    function paused() public view returns (bool) {
+        return _paused;
+    }
+
+    /**
+     * @dev Modifier to make a function callable only when the contract is not paused.
+     */
+    modifier whenNotPaused() {
+        require(!_paused);
+        _;
+    }
+
+    /**
+     * @dev Modifier to make a function callable only when the contract is paused.
+     */
+    modifier whenPaused() {
+        require(_paused);
+        _;
+    }
+
+    /**
+     * @dev called by the owner to pause, triggers stopped state
+     */
+    function pause() public onlyPauser whenNotPaused {
+        _paused = true;
+        emit Paused(_msgSender());
+    }
+
+    /**
+     * @dev called by the owner to unpause, returns to normal state
+     */
+    function unpause() public onlyPauser whenPaused {
+        _paused = false;
+        emit Unpaused(_msgSender());
+    }
+
+    uint256[50] private ______gap;
+}

contracts/math/Math.sol

@@ -0,0 +1,31 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title Math
+ * @dev Assorted math operations
+ */
+library Math {
+    /**
+     * @dev Returns the largest of two numbers.
+     */
+    function max(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a >= b ? a : b;
+    }
+
+    /**
+     * @dev Returns the smallest of two numbers.
+     */
+    function min(uint256 a, uint256 b) internal pure returns (uint256) {
+        return a < b ? a : b;
+    }
+
+    /**
+     * @dev Calculates the average of two numbers. Since these are integers,
+     * averages of an even and odd number cannot be represented, and will be
+     * rounded down.
+     */
+    function average(uint256 a, uint256 b) internal pure returns (uint256) {
+        // (a + b) / 2 can overflow, so we distribute
+        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
+    }
+}

contracts/math/SafeMath.sol

@@ -0,0 +1,65 @@
+pragma solidity ^0.5.2;
+
+/**
+ * @title SafeMath
+ * @dev Unsigned math operations with safety checks that revert on error
+ */
+library SafeMath {
+    /**
+     * @dev Multiplies two unsigned integers, reverts on overflow.
+     */
+    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
+        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
+        // benefit is lost if 'b' is also tested.
+        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
+        if (a == 0) {
+            return 0;
+        }
+
+        uint256 c = a * b;
+        require(c / a == b);
+
+        return c;
+    }
+
+    /**
+     * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
+     */
+    function div(uint256 a, uint256 b) internal pure returns (uint256) {
+        // Solidity only automatically asserts when dividing by 0
+        require(b > 0);
+        uint256 c = a / b;
+        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
+
+        return c;
+    }
+
+    /**
+     * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
+     */
+    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
+        require(b <= a);
+        uint256 c = a - b;
+
+        return c;
+    }
+
+    /**
+     * @dev Adds two unsigned integers, reverts on overflow.
+     */
+    function add(uint256 a, uint256 b) internal pure returns (uint256) {
+        uint256 c = a + b;
+        require(c >= a);
+
+        return c;
+    }
+
+    /**
+     * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
+     * reverts when dividing by zero.
+     */
+    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
+        require(b != 0);
+        return a % b;
+    }
+}

contracts/mocks/Acknowledger.sol

@@ -0,0 +1,19 @@
+pragma solidity ^0.5.2;
+
+contract Acknowledger {
+    event AcknowledgeFoo(uint256 a);
+    event AcknowledgeBarSingle(uint256 a);
+    event AcknowledgeBarDouble(uint256 a, uint256 b);
+
+    function foo(uint256 a) public {
+        emit AcknowledgeFoo(a);
+    }
+
+    function bar(uint256 a) public {
+        emit AcknowledgeBarSingle(a);
+    }
+
+    function bar(uint256 a, uint256 b) public {
+        emit AcknowledgeBarDouble(a, b);
+    }
+}

contracts/mocks/AddressImpl.sol

@@ -0,0 +1,9 @@
+pragma solidity ^0.5.2;
+
+import "../utils/Address.sol";
+
+contract AddressImpl {
+    function isContract(address account) external view returns (bool) {
+        return Address.isContract(account);
+    }
+}

contracts/mocks/AllowanceCrowdsaleImpl.sol

@@ -0,0 +1,13 @@
+pragma solidity ^0.5.2;
+
+import "../token/ERC20/IERC20.sol";
+import "../crowdsale/emission/AllowanceCrowdsale.sol";
+
+contract AllowanceCrowdsaleImpl is AllowanceCrowdsale {
+    constructor (uint256 rate, address payable wallet, IERC20 token, address tokenWallet)
+        public
+    {
+        Crowdsale.initialize(rate, wallet, token);
+        AllowanceCrowdsale.initialize(tokenWallet);
+    }
+}