Error: assertion failed: an Ember.CollectionView's content must implement Ember.Array. You passed Ol.SubjectsController

index.html.erb

<script type="text/x-handlebars">
  {{view Ol.ListSubjectsView}}
</script>

list.handlebars

<h1>Subjects</h1>
{{#each Ol.SubjectsController}}
<li>{{subject}}</li>
{{/each}}
{{outlet}}

list.js

Ol.ListSubjectsView = Ember.View.extend({
  templateName: 'subjects/list',
  subjectsBinding: 'Ol.SubjectsController'
});

subjects_controller.js

Ol.SubjectsController = Ember.ArrayController.extend({
  content: Ol.store.findAll(Ol.Subject)
});