title: ionic 3 EmailValidator usage
body: <p>I'm using newest ionic framework and I see that angular dev team added <code>EmailValidator</code> feature. But it's a little bit unclear how I should use it. Can anybody give me an example of usage?</p>
  
  <p>home.html</p>
  
  <pre><code>&lt;ion-content padding&gt;
  
      &lt;ion-list&gt;
  
          &lt;ion-item margin-vertical&gt;
              &lt;ion-label&gt;Enter email&lt;/ion-label&gt;
              &lt;ion-input type="email" name="email" [(ngModel)]="email"&gt;&lt;/ion-input&gt;
          &lt;/ion-item&gt;
  
      &lt;/ion-list&gt;
  
      &lt;button (type)="button" ion-button block large [disabled]="!email" (click)="checkValidation()"&gt;Check!&lt;/button&gt;
  
  &lt;/ion-content&gt;
  </code></pre>
  
  <p>home.ts</p>
  
  <pre><code>import { Component } from '@angular/core';
  import { IonicPage } from 'ionic-angular';
  import { EmailValidator } from '@angular/forms';
  
  @IonicPage()
  @Component({
       selector: 'page-login',
       templateUrl: 'home.html'
  })
  
  export class LoginPage  {
      email: string;
  
      constructor() {}
  
      checkValidation() : string () {
          // validation here
      }
  
  }
  </code></pre>