title: How to get the selected value from ionic radio-group
body: <p>I have a radio group in Ionic and when I returned the value selected by this group I get "undefined".</p>
  
  <pre><code>&lt;ion-list radio-group [(ngModel)]="myType"&gt;
        &lt;ion-radio value="1"&gt;Type 1&lt;/ion-radio&gt;
        &lt;ion-radio value="2"&gt;Type 2&lt;/ion-radio&gt;
        &lt;ion-radio value="3"&gt;Type 3&lt;/ion-radio&gt;
  &lt;/ion-list&gt;
  </code></pre>
  
  <p>and in the controller I try to access the value like this:</p>
  
  <pre><code>console.log($scope.myType);  // returnes undefined 
  </code></pre>