remove post install script

Author: Apoorva P

package.json

@@ -8,8 +8,7 @@
     "lint": "eslint .",
     "postpublish": "git push origin master --tags",
     "test": "ava",
-    "integration-test": "node __tests__/_integration.js",
-    "postinstall": "cd node_modules/[PACKAGE_NAME] && npm install && npm run build"
+    "integration-test": "node __tests__/_integration.js"
   },
   "repository": {
     "type": "git",