title: Installed pwa won't launch offline
body: <p>i've made a PWA using webpack offline plugin, configured this way : </p>
  
  <pre><code>// Put it in the end to capture all the HtmlWebpackPlugin's
  // assets manipulations and do leak its manipulations to HtmlWebpackPlugin
  new OfflinePlugin({
    ServiceWorker: {
      events: true,
    },
    relativePaths: false,
    publicPath: '/',
    appShell: '/',
  
    // No need to cache .htaccess. See http://mxs.is/googmp,
    // this is applied before any match in `caches` section
    excludes: ['.htaccess'], // index.html
  
    caches: {
      main: [':rest:'],
  
      // All chunks marked as `additional`, loaded after main section
      // and do not prevent SW to install. Change to `optional` if
      // do not want them to be preloaded at all (cached only when first loaded)
      additional: ['*.chunk.js'],
    },
  
    // Removes warning for about `additional` section usage
    safeToUseOptionalCaches: true,
    autoUpdate: true,
  }),
  
  new WebpackPwaManifest({
    name: 'my_app_name',
    short_name: 'my_app_short_name',
    description: 'my_app_description',
    background_color: '#364150',
    theme_color: '#b1624d',
    icons: [
      {
        src: path.resolve('app/images/icon-512x512.png'),
        sizes: [72, 96, 120, 128, 144, 152, 167, 180, 192, 384, 512],
      },
    ],
  }),
  </code></pre>
  
  <p>So the service worker works and i can see it on chrome devtools.
  The pwa is recognised by chrome and as i navigate to my url (hosted by heroku in https) chrome prompts with installation advice on mobile.
  I then install the app to my android phone, log in and use it as always. When i go offline everything still works, i can navigate throughout my app, i can minimize it and reopen, so far so good.
  When i CLOSE my app ( with task manager), i go OFFLINE, and i open it it will prompt with either a white page or a no connection prompt.
  Any tips? 
  In addiction, how does it actually work? Everytime i click on the installed pwa it checks if i have connection and download the (if present) newer version of the app?</p>