title: Angular 1: Change md-checkbox depending on input checkbox
body: <p>How do I change check status of <code>md-checkbox</code> from Angular material depending on the actual checkbox check status? </p>
  
  <p>Here are my checkboxes. They are inside <code>ng-repeat</code>. </p>
  
  <pre><code>    &lt;input type="checkbox" ng-checked="item.completed" ng-model="toDoItemCheckbox"&gt;
      &lt;md-checkbox
        ng-change="toggleToDoItem({{item.createdAt}})" ng-model="toDoItemCheckbox" aria-label="todo-checkbox"&gt;
      &lt;/md-checkbox&gt;
  </code></pre>