title: Vue.js: can't orderBy in v-for
body: <p>I've upgraded to Vue.js 2.0.5 and orderBy in a v-for seems to not be working anymore</p>
  
  <pre><code>&lt;li v-for="c in rooms | orderBy 'last_iteraction'"&gt;
  </code></pre>
  
  <p>outputs</p>
  
  <blockquote>
    <ul>
    <li>invalid expression: v-for="c in rooms | orderBy 'last_iteraction'"</li>
    </ul>
  </blockquote>
  
  <p>anyone knows how to solve?</p>