title: default value for Select dropdown with Angular 6
body: <p>I have a select input: </p>
  
  <pre><code>&lt;select id="duration" name="duration" class="form-control select-lg"
            [(ngModel)]="championship.settings.fightDuration"&gt;
      &lt;option *ngFor="let duration of durations"
            [selected]="championship.settings.fightDuration==duration"&gt; 
            {{ duration }} {{ championship.settings.fightDuration==duration }}
      &lt;/option&gt;
  &lt;/select&gt;
  </code></pre>
  
  <p>I have his value within <code>championship.settings.fightDuration</code></p>
  
  <p>I try to preselect it with:</p>
  
  <pre><code>[selected]="championship.settings.fightDuration==duration"
  </code></pre>
  
  <p>I in select text, I print the result of this condition, and it prints <code>true</code> on the element that matches the values, so it should work, but select has no selected value... </p>
  
  <p>What am I missing ?</p>