Added es6-promise polyfill in browsers.

Author: Aamod Pisat

package.json

@@ -74,6 +74,7 @@
     "string-replace-loader": "1.3.0"
   },
   "dependencies": {
+    "es6-promise": "4.1.1",
     "isomorphic-fetch": "2.2.1",
     "localStorage": "1.0.3"
   }