title: Counting model with ember data
body: <p>I've looked at various examples on Stackoverflow but I don't seem to understand how get('length') really works.</p>
  
  <p>I'm trying to get a count of users in helper model. There is probably something wrong with the way I'm trying to get('length'), but maybe I also need to use hash RSVP to get both the current model and helper model in todo route?</p>
  
  <p>todo.js</p>
  
  <pre><code>export default Ember.Controller.extend({
  
      count: function() {
          var helper = this.get('helper');
          return helper.user.get('length');
      }.property('helper.user.[]'),
  </code></pre>
  
  <p>todo.js</p>
  
  <pre><code>export default DS.Model.extend({
      title: DS.attr('string'),
      isCompleted: DS.attr('boolean', {defaultValue: false}),
  
      list: DS.belongsTo('list', {async: true}),
      user: DS.belongsTo('user', {async: true}),
  
      comment: DS.hasMany('comment', {async: true}),
      helper: DS.hasMany('helper', {async: true}),
  });
  </code></pre>
  
  <p>todo.hbs</p>
  
  <pre><code>&lt;p&gt;
                      &lt;span class="badge pull-left"&gt;14 hands&lt;/span&gt;
                      &lt;span class="badge pull-left"&gt;{{todo.count}}&lt;/span&gt;
                      &lt;/p&gt;
  </code></pre>
  
  <p>helper.js</p>
  
  <pre><code>export default DS.Model.extend({
      user: DS.belongsTo('user', {async: true}),
      todo: DS.belongsTo('todo', {async: true}),
  });
  </code></pre>
  
  <p>todo.js</p>
  
  <pre><code>export default Ember.Route.extend({
    model: function(params){
      // return model
    },
  </code></pre>