title: Angular 2 Can't get ngModel to work right with checkbox
body: <p>I have an edit form where the data comes from a database with an array of role objects that consists of a name and a selected property. I have a checkbox for each role object in the array. When the form loads, the checkbox is not checked even though looking at the object the selected property is true. If I check a checkbox the role.selected value in the label below changes so I'm not sure why the checkbox won't be checked when the form first loads. I've tried adding <code>[value]="role.selected"</code> and <code>[checked]="role.selected"</code> and that doesn't change anything. Any help is greatly appreciated. I'm sure it's something simple that I can't see after looking at it for hours. </p>
  
  <pre><code>&lt;div class="checkbox" *ngFor="let role of userToEdit.allRoles"&gt;
       &lt;label&gt;&lt;input type="checkbox" name="role" [(ngModel)]="role.selected" &gt;{{role.name}}, {{role.selected}}&lt;/label&gt;
  &lt;/div&gt;
  </code></pre>