fix polyfill (closes #348)

Author: bertho-zero

.babelrc

@@ -7,7 +7,8 @@
         "targets": {
           "browsers": ["last 2 versions", "IE >= 8"],
           "node": "current"
-        }
+        },
+        "useBuiltIns": "entry"
       }
     ],
     "stage-0"

server.babel.js

@@ -1,4 +1,5 @@
 //  enable runtime transpilation to use ES6/7 in node
+require('babel-polyfill');
 
 var fs = require('fs');
 

src/config.js

@@ -1,5 +1,3 @@
-require('babel-polyfill');
-
 const environment = {
   development: {
     isProduction: false,