title: Angular.js required at least one checkbox
body: <p>I wouldn't be surprised if this is a duplicate however I can't find anything simple along the lines of what I need.</p>
  
  <p>All I need is the user to be required to choose at least one checkbox but I'm baffled how to accomplish this.</p>
  
  <pre><code>    &lt;input type="checkbox" ng-model="myForm.first" /&gt; First &lt;br /&gt;
      &lt;input type="checkbox" ng-model="myForm.second" /&gt;Second &lt;br /&gt;
      &lt;input type="checkbox" ng-model="myForm.third" /&gt; Third
  </code></pre>