gistfile1.handlebars

<section class="l-container">
  <ul class="list--vertical">
    {{#each project in controller}}
      <li>{{project.name}} ({{project.tasks.length}})</li>
    {{/each}}
  </ul>
</section>

gistfile2.json

{"projects":[{"id":1,"name":"Build Patio","details":null,"task_ids":[1,2]},{"id":2,"name":"Clean the house","details":null,"task_ids":[]}]}