title: AngularFirebase FirebaseListObservable can't get get uid
body: <p>I have a list of Users which I want to display.
  Which works, I can display the usernames but not the keys.
  {{user.uid}} or {{user.key}} prints out nothing, {{user.username}} all the names.
  Any Idea?</p>
  
  <p>My Structure looks like that:</p>
  
  <p><a href="https://i.stack.imgur.com/mp9Tw.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mp9Tw.png" alt="enter image description here"></a></p>
  
  <p>Component.ts</p>
  
  <pre><code>    allUsers: FirebaseListObservable&lt;any[]&gt;;
  
    constructor(private afAuth: AngularFireAuth,
      private db: AngularFireDatabase, private router: Router) {
  
        this.allUsers = db.list('/users');
     }
  </code></pre>
  
  <p>Component.html</p>
  
  <pre><code>  &lt;ul class="list-group gamer-list"&gt;
    &lt;li class="list-group-item agamer" *ngFor="let user of allUsers | async"&gt;
      &lt;div class="material-switch"&gt;
       &lt;input id="switch{{user.username}}" name="switch{{user.username}}" type="checkbox"/&gt;
       &lt;label for="switch{{user.username}}" class="switch{{user.username}}"&gt;&lt;/label&gt;
                      &lt;/div&gt;
                      {{user.key}} - {{user.username}}
                  &lt;/li&gt;
          &lt;/ul&gt;
  </code></pre>