Added the repository field and a script for after npm version (#2459)

package.json

@@ -2,12 +2,17 @@
   "name": "mastodon",
   "license": "AGPL-3.0",
   "scripts": {
+    "postversion": "git push --tags",
     "start": "babel-node ./streaming/index.js --presets es2015,stage-2",
     "storybook": "start-storybook -p 9001 -c storybook",
     "test": "npm run test:lint && npm run test:mocha",
     "test:lint": "eslint -c .eslintrc.json --ext=js --ext=jsx app/assets/javascripts/",
     "test:mocha": "mocha --require ./spec/javascript/setup.js --compilers js:babel-register ./spec/javascript/components/*.test.jsx"
   },
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/tootsuite/mastodon.git"
+  },
   "dependencies": {
     "@kadira/storybook": "^2.35.3",
     "axios": "^0.15.3",