title: Ember DS.Store.findAll() returns empty collection
body: <p>Hey I need to modify some records which I get from the DataStore. If I add the following code in my router I can see that the requests get passed to my template, but I can't modify each request of the collection because the collection is empty.  </p>
  
  <pre><code>model() {
    return this.store.findAll('user').then(function(users) {
      console.log(users.get('length')); // 0
      return users;
    });
  }
  </code></pre>
  
  <p>I thought that the promise gets resolved when all the records have been fetched from the server but this doesn't seem to be the case. Or did I completely miss something.</p>
  
  <p>I also tried to modify the model in the afterModel callback with the same result. </p>
  
  <p>I'm using Ember 1.13.0 (with Ember-CLI), Ember-Data 1.13.4 and ember-cli-mirage for Mocking my HTTP Requests.</p>
  
  <p><strong>UPDATE:</strong>
  I managed to create a workaround for this issue. In my controller, I created a new property which listens for model.@each and then I was able to modify model and pass it to the view.</p>
  
  <pre><code>export default Ember.Controller.extend({
    users: function() {
      return this.get('model.users').filter(function(user) {
        // The Promise is resolved twice
        // The first time with an empty model and the second time with 
        // the actual data. So I filter the empty model. 
        return user.get('id');
      }).map(function(user) {
        // do fancy stuff with our user
        return user
      });
    }.property('model.@each')
  });
  </code></pre>