New documentation setup (#1708)

* initial docsite setup

* switch from pushd to cd

* install and set up solidity-docgen

* use the docsite branch next for now

* make it clear that env var is a repository

* add a clarifying comment about a relative path

* change relative to absolute path in docsite script

* add docgen script

* add first few READMEs for contract documentation

* update solidity-docgen

* add docsite as dependency and adjust script

* update openzeppelin-docsite

* update solidity-docgen

* remove dummy text

* update docgen and docsite

* update openzeppelin-docsite

* add netlify.toml

* udpate tokens guide for 2.2

* add DOCUMENTATION.md

* Update docs/learn-about-utilities.md

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

* fix PaymentSplitter docs wording

* update solidity-docgen

* add missing ERC20 contracts

* update solidity-docgen

* trigger deploy with cleared cache

* update solidity-docgen

* update openzeppelin-docsite

* remove travis docs setup

* update openzeppelin-docsite

* switch to published solidity-docgen

docs/get-started.md

@@ -0,0 +1,51 @@
+---
+id: get-started
+title: Get Started
+---
+
+OpenZeppelin can be installed directly into your existing node.js project with `npm install --save-exact openzeppelin-solidity`, but OpenZeppelin also integrates directly with [Truffle](https://github.com/ConsenSys/truffle), an Ethereum development environment, which we'll use to get started.
+
+Please install Truffle and initialize your project:
+
+```sh
+$ npm install -g truffle
+$ mkdir myproject && cd myproject
+$ truffle init
+```
+
+To install the OpenZeppelin library, run the following in your Solidity project root directory:
+```sh
+$ npm init -y
+$ npm install --save-exact openzeppelin-solidity
+```
+
+**Note that OpenZeppelin only lightly follows semantic versioning.** You may encounter breaking changes upon a minor version bump. We recommend pinning the version of OpenZeppelin you use by using the `--save-exact` option.
+
+After that, you'll get all the library's contracts in the `node_modules/openzeppelin-solidity/contracts` folder. Because Truffle and other Ethereum development toolkits understand `node_modules`, you can use the contracts in the library like so:
+
+```js
+import 'openzeppelin-solidity/contracts/ownership/Ownable.sol';
+
+contract MyContract is Ownable {
+  ...
+}
+```
+
+## Next Steps
+
+After installing OpenZeppelin, check out the rest of the guides in the sidebar to learn about the different contracts that OpenZeppelin provides and how to use them.
+
+- [Learn About Access Control](/api/docs/learn-about-access-control.html)
+- [Learn About Crowdsales](/api/docs/learn-about-crowdsales.html)
+- [Learn About Tokens](/api/docs/learn-about-tokens.html)
+- [Learn About Utilities](/api/docs/learn-about-utilities.html)
+
+You may also want to take a look at the guides which cover several common use cases and good practices: https://blog.zeppelin.solutions/guides/home
+
+For example, [The Hitchhiker’s Guide to Smart Contracts in Ethereum](https://blog.zeppelin.solutions/the-hitchhikers-guide-to-smart-contracts-in-ethereum-848f08001f05) will help you get an overview of the various tools available for smart contract development, and help you set up your environment.
+
+[A Gentle Introduction to Ethereum Programming, Part 1](https://blog.zeppelin.solutions/a-gentle-introduction-to-ethereum-programming-part-1-783cc7796094) provides very useful information on an introductory level, including many basic concepts from the Ethereum platform.
+
+For a more in-depth dive, you may read the guide [Designing the architecture for your Ethereum application](https://blog.zeppelin.solutions/designing-the-architecture-for-your-ethereum-application-9cec086f8317), which discusses how to better structure your application and its relationship to the real world.
+
+You may also ask for help or follow OpenZeppelin's progress in the community [forum](https://forum.zeppelin.solutions), or read OpenZeppelin's full API on this website.