installExtensions = async () => {
  const installer = require('electron-devtools-installer');
  const forceDownload = !!process.env.UPGRADE_EXTENSIONS;
  const extensions = [
    'REACT_DEVELOPER_TOOLS',
    'REDUX_DEVTOOLS'
  ];

  return Promise
    .all(extensions.map(name => installer.default(installer[name], forceDownload)))
    .catch(console.log);
}
This module executes inside of electron's main process. You can start
electron renderer process from here and communicate with the other processes
through IPC.

When running `npm run build` or `npm run build-main`, this file is compiled to
`./app/main.prod.js` using webpack. This gives us some performance wins.

@flow