function createWindow () {
  /**
   * Initial window options
   */
  mainWindow = new BrowserWindow({
    useContentSize: true,
    width: windowWidth,
    height: 600,
    minWidth: 800,
    minHeight: 600
  })

  mainWindow.loadURL(winURL)

  mainWindow.on('closed', () => {
    mainWindow = null
  })
}
Set `__static` path to static files in production
https://simulatedgreg.gitbooks.io/electron-vue/content/en/using-static-assets.html