title: Invite friends to the game (not multiplayer)
body: <p>I'm currently showing a leaderboard in my game using Google Play Games. Now I want to add an "Invite" button in order to engage more users to the game, the idea is when you press the button, show a popup with all the friends in your circles, select one or more and then send the invites.</p>
  
  <p>I've looked through the API but can't find anything. Weird thing is that this feature appears in the landing page of Google Play Services (<a href="https://developers.google.com/games/services/" rel="nofollow">https://developers.google.com/games/services/</a>):</p>
  
  <blockquote>
    <p>Help players ask friends to take specific action in a game, like "challenge", "attack", or "accept gift".</p>
  </blockquote>
  
  <p>So maybe I'm missing something. Is this possible to do? How?</p>