add version script to update ethpm.json (#906)

package.json

@@ -11,7 +11,8 @@
     "lint:all": "npm run lint && npm run lint:sol",
     "lint:all:fix": "npm run lint:fix && npm run lint:sol:fix",
     "console": "truffle console",
-    "coverage": "scripts/coverage.sh"
+    "coverage": "scripts/coverage.sh",
+    "version": "scripts/version.js"
   },
   "repository": {
     "type": "git",

scripts/version.js

@@ -0,0 +1,16 @@
+#!/usr/bin/env node
+
+// Synchronizes ethpm.json version number with package.json.
+// Useful to run as an npm script alogn with `npm version`.
+
+const fs = require('fs');
+const cp = require('child_process');
+
+const pkg = require('../package.json');
+const ethpm = require('../ethpm.json');
+
+ethpm.version = pkg.version;
+
+fs.writeFileSync('ethpm.json', JSON.stringify(ethpm, null, 2) + '\n');
+
+cp.execSync('git add ethpm.json');