title: In angular formly, how to add ng-click or ng-change to a checkbox?
body: <p>I am using angular-formly, I am trying to add the normal angular events to a checkbox but no joy. Here is what I have:</p>
  
  <pre><code>{
      type: "checkbox",
      key: "is_active",
      templateOptions: {
          type: "",
          label: "Is Active"
      }
  }
  </code></pre>
  
  <p>I looked over the documentations over and over and I can not find the solution. Please show where to add ng-click or ng-change in the above.</p>
  
  <p>I hoped something like the below would work:</p>
  
  <pre><code>{
      type: "checkbox",
      key: "is_active",
      templateOptions: {
          type: "",
          label: "Is Active"
      },
      ngClick : "functionName"
  }
  </code></pre>
  
  <p>where <code>functionName</code> is a function inside the controller that renders the form. So my functions will always be in my controller, I just need to define or pass the event to the checkbox</p>