Transition to show only complete todos

http://guides.emberjs.com/v1.10.0/getting-started/show-only-complete-todos/

```
ember g route todos/completed
rm app/templates/todos/completed.hbs
```

app/router.js

@@ -10,6 +10,7 @@ Router.map(function() {
     path: '/'
   }, function() {
     this.route('active');
+    this.route('completed');
   });
 });
 

app/routes/todos/completed.js

@@ -0,0 +1,12 @@
+import Ember from 'ember';
+
+export default Ember.Route.extend({
+  model: function(){
+    return this.store.filter('todo', function(todo) {
+      return todo.get('isCompleted');
+    });
+  },
+  renderTemplate: function(controller) {
+    this.render('todos/index', {controller: controller});
+  }
+});

app/templates/todos.hbs

@@ -27,7 +27,7 @@
         {{#link-to "todos.active" activeClass="selected"}}Active{{/link-to}}
       </li>
       <li>
-        <a href="completed">Completed</a>
+        {{#link-to "todos.completed" activeClass="selected"}}Completed{{/link-to}}
       </li>
     </ul>
 

tests/unit/routes/todos/completed-test.js

@@ -0,0 +1,14 @@
+import {
+  moduleFor,
+  test
+} from 'ember-qunit';
+
+moduleFor('route:todos/completed', {
+  // Specify the other units that are required for this test.
+  // needs: ['controller:foo']
+});
+
+test('it exists', function(assert) {
+  var route = this.subject();
+  assert.ok(route);
+});