title: ember.js authentication
body: <p>I would like to implement authentication with ember.js.
  So, when the application start, before the Router handles the requested url, I want to check the user status. If the user isn't authenticated, I want to save the requested url and redirect to a specific url (/login).
  I tried to implement this overloading Ember.Route but I don't think it's a good practice.
  For example, if i do:</p>
  
  <pre><code>var AuthRoute = Ember.Route.extend({  
      redirect: function() {  
          var controller = App.userController;  
              if (!controller.get("userAuth")) {  
                  controller.set("lastFilter", this.routeName);  
                  this.transitionTo("index");
              }  
          }  
      }  
  });
  </code></pre>
  
  <p>If, the url is '/admin/foobar', the admin route will redirect instead of foobar.</p>
  
  <p>Can I process redirection before the Router to start?</p>