title: How can I use a ngModel on an ion-radio element?
body: <p>I'm trying to implement a ngModel on a ion-radio element but somehow it doesn't work. This is my code:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>import {
    Page
  } from 'ionic-angular';
  
  @Page({
    templateUrl: 'build/pages/settings/settings.html'
  })
  
  export class Settings {
    constructor() {
      this.unit = 2;
    }
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;ion-list radio-group&gt;
    &lt;ion-list-header&gt;
      Unit
    &lt;/ion-list-header&gt;
  
    &lt;ion-item&gt;
      &lt;ion-label&gt;Metric (kg)&lt;/ion-label&gt;
      &lt;ion-radio value="1" [(ngModel)]="unit"&gt;&lt;/ion-radio&gt;
    &lt;/ion-item&gt;
  
    &lt;ion-item&gt;
      &lt;ion-label&gt;Imperial (lbs)&lt;/ion-label&gt;
      &lt;ion-radio value="2" [(ngModel)]="unit"&gt;&lt;/ion-radio&gt;
    &lt;/ion-item&gt;
  &lt;/ion-list&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I've tried implementing it on a ion-input and ion-select and that just works fine. I also tried adding <code>directives: [FORM_DIRECTIVES]</code> to my @Page and added the corresponding import but that doesn't fix the problem.</p>
  
  <p>Any ideas? </p>