title: Filter multiple models by attribute in ember.js Route
body: <p>I have the following RSVP hash in my IndexRoute which finds all slider records ( I need to use a hash because I need to load 2 models on this page). I can call sliders or this.sliders in the index template to successfully pass all the slider objects to a view component.</p>
  
  <p>However, I need to filter these records by the page attribute "index". When I add filterBy to the IndexRoute, no records are returned.</p>
  
  <p>How can I filter these records and use the resulting array in the template?</p>
  
  <p>IndexRoute</p>
  
  <pre><code>App.IndexRoute = Ember.Route.extend({
      model: function() {
          return Ember.RSVP.hash({ 
              sliders: this.store.findAll("slider"), # Adding .filterBy("page", "index") fails to load anything
              products: this.store.findAll("products")
          });
      }
  });
  </code></pre>
  
  <p>index.html</p>
  
  <pre><code>&lt;script type="text/x-handlebars" data-template-name="index"&gt;
     {{mainpage-slider sliders=sliders}}
  &lt;/script&gt;
  </code></pre>