title: Pass data to ionic2 menu
body: <p>I am having a menu whose html i have written in app.html-</p>
  
  <pre><code>&lt;ion-menu [content]="mycontent"&gt;
    &lt;ion-toolbar class = "menuUserName"&gt;
      &lt;ion-title&gt;{{userName}}&lt;/ion-title&gt;
    &lt;/ion-toolbar&gt;
    &lt;ion-content&gt;
      &lt;ion-list&gt;
        ...
       &lt;/ion-list&gt;
    &lt;/ion-content&gt;
  &lt;/ion-menu&gt;
  
  &lt;ion-nav #mycontent [root]="rootPage"&gt;&lt;/ion-nav&gt;
  </code></pre>
  
  <p>My app flow is login->homepage.
  when the user login the app,it will get username from a service.
  How can i pass this data to my ionic2 menu to update username.</p>