add a re-install script

package.json

@@ -20,6 +20,7 @@
   },
   "scripts": {
     "start": "electron app --disable-http-cache",
+    "reinstall": "rm -rf node_modules; rm -rf app/node_modules; npm install",
     "postinstall": "electron-builder install-app-deps",
     "test": "xo",
     "dev": "gulp dev",