title: how to use notification badges with onesignal?
body: <p>I'd like to use the notification-badge-counter in ios in my ionic-app.
  The notifications already work but if I add <code>ios_badgeType</code> and <code>ios_badgeCount</code> to the notificationObject, I'm getting an error (<code>"All included players are not subscribed"</code>) .</p>
  
  <p>This is my notificationObject:</p>
  
  <pre><code>var notificationObj = {
      contents: {en: "message"},
      include_player_ids: pushIDs,
      ios_badgeType: 'increase',
      ios_badgeCount: 1
      };
  </code></pre>
  
  <p>which is posted like this:</p>
  
  <pre><code>window.plugins.OneSignal.postNotification(notificationObj,
  function(successResponse) {
      console.log("Notification Post Success:", successResponse);
  },
  function (failedResponse) {
      console.log("Notification Post Failed: ", failedResponse);
  });
  </code></pre>
  
  <p>note: <code>pushIDs</code> is an array containing correct playerIDs.</p>
  
  <p>What am i missing? </p>