title: Validating a transition using the new Async Ember router
body: <p>Using the non-async router, we could expect redirect on a route to be called only after resolving promises on from the model function. That's no longer the case. </p>
  
  <p>How can something like this be implemented today?</p>
  
  <pre><code>App.ClientRoute = Ember.Route.extend
    model: (params) -&gt; 
      App.Client.findById params.client_id
  
    redirect: -&gt;
      unless @modelFor 'client'
        @transitionTo 'clients' 
  </code></pre>