Updated example in readme to use ReactDOM.render

[brendannee]

No description provided.

[knowbody]

@brendannee to be consistent and to use ES6 features, this is how we do it everywhere else:

import { render } from 'react-dom'

please, apply the change and rebase and I'll merge it

[brendannee]

Thanks, I updated the commit based on your suggestion.

[taion]

Thanks!