To repro:

1. npm start
2. Open localhost:8080 in the browser
3. Observe blank page, error messages in console about Group not being a valid React element
4. Crtl+C the webpack-dev-server
5. Comment out the 'react-hot-loader/patch', line in webpack.config.js
6. npm start
7. Open localhost:8080 in the browser
8. Observe the page renders properly