title: Multiple push notifications using ionic push
body: <p>When sending two notifications the second one always overrides the first one in the notification center.
  According to the <a href="http://docs.ionic.io/docs/push-sending-push" rel="nofollow">docs</a> this should happen only when using the tag:</p>
  
  <blockquote>
    <p>"tag": Indicates whether each notification message results in a new
    entry on the notification center. If not set, each request creates a
    new notification. If set, and a notification with the same tag is
    already being shown, the new notification replaces the existing one.</p>
  </blockquote>
  
  <p>However this happens to me all the time, regardless whether I set a value for the tag or not.</p>
  
  <p>I even tried setting a random tag &amp; collapse_key (which as far I understand shouldn't be related in this case, but I gave it a try). Still didn't help.
  Here's a sample of a notification object I'm sending:</p>
  
  <pre><code>{  
     "tokens":[  
        "my-device-token"
     ],
     "profile":"my-profile-tag",
     "notification":{  
        "message":"message",
        "android":{  
           "payload":{  
              "collapse_key":9918519,
              "tag":2825928
           }
        }
     }
  }
  </code></pre>