title: What should we do to run NSoperationqueue after app enters applicationDidEnterBackground?
body: <p>I want to download even when app enters in bacground after quiting home button.But Will NSoperationqueue do it automatically ?
    should I set UI Background Modes in Plist with value "Fetch" ?</p>
  
  <p>If it is possible to run NSoperationqueue in app background mode, Will UIupdation happen only after entering foreground only?</p>
  
  <pre><code>Any tutorial or example please ?
  </code></pre>