title: When i do the login i should change the page
body: <p><strong>Unable to get property 'push' of undefined or null reference</strong></p>
  
  <pre><code>Accesso(){
      $.get("http://localhost:4000/utente?matricola="+this.username+"&amp;password="+this.pass)
      .done(function(data){
          if(data=="Errore")
              alert("Errore");
          else{
              alert("success - "+data);
              this.navCtrl.push(TabsPage[0]);
          }
      })
      .fail(function(data){
          alert("error- " + data);
      });
  }
  </code></pre>