import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import registerServiceWorker from './registerServiceWorker';
import firebase from 'firebase';
import config from './config';

firebase.initializeApp( config.firebase );

ReactDOM.render(<App />, document.getElementById('root'));
registerServiceWorker();

import React from 'react';
import ReactDOM from 'react-dom';
import './index.css';
import App from './App';
import registerServiceWorker from './registerServiceWorker';
import * as firebase from 'firebase';
import config from './config';

firebase.initializeApp( config.firebase );

ReactDOM.render(<App />, document.getElementById('root'));
registerServiceWorker();

Update firebase import