set env variables config in webpack file

src/index.js

@@ -1,6 +1,6 @@
 import React from 'react';
 import ReactDOM from 'react-dom';
-import { BrowserRouter } from "react-router-dom";
+import { BrowserRouter } from 'react-router-dom';
 import { Provider } from 'react-redux';
 import { createStore, applyMiddleware } from 'redux';
 import reducers from './store/reducers';
@@ -13,11 +13,11 @@ import './static/sass/style.scss';
 const createStoreWithMiddleware = applyMiddleware(promise)(createStore);
 
 const app = (
-   <Provider store={createStoreWithMiddleware(reducers)}>
-      <BrowserRouter>
-         <App />
-      </BrowserRouter>
-   </Provider>
+  <Provider store={createStoreWithMiddleware(reducers)}>
+    <BrowserRouter>
+      <App />
+    </BrowserRouter>
+  </Provider>
 );
 
-ReactDOM.render(app, document.getElementById('app'));
+ReactDOM.render(app, document.getElementById('app'));