title: angular2 cannot read property 'validator' of undefined when use ngFormModel (ES6)
body: <p>I got some problem when use ngFormModel directive with form
  it said "TypeError: Cannot read property 'validator' of undefined in form_one (I write this code from NG-BOOK 2 Tutorial but it's not work!)</p>
  
  <pre><code>import {Component} from 'angular2/core'
  import {
    FORM_DIRECTIVES,
    FormBuilder,
    ControlGroup,
    Validators
  } from 'angular2/common'
  
  @Component({
    selector: 'demo-form-sku-builder',
    directives: [FORM_DIRECTIVES],
    template: `
    &lt;div class="ui raised segment"&gt;
      &lt;h2 class="ui header"&gt;Demo Form: Sku with FormBuilder&lt;/h2&gt;
      &lt;form class="ui form"
        [ngFormModel]="myForm"
        (ngSubmit)="onSubmit(myForm.value)"&gt;
        &lt;div class="field"&gt;
          &lt;label for="skuInput"&gt;SKU&lt;/label&gt;
          &lt;input type="text"
            id="skuInput"
            placeholder="SKU"
            [ngFormControl]="myForm.controls['sku']"&gt;
        &lt;/div&gt;
  
        &lt;button type="submit" class="ui button"&gt;Submit&lt;/button&gt;
      &lt;/form&gt;
    &lt;/div&gt;
    `
  })
  export class DemoFormSkuBuilder {
  
    contructor (formBuilder) {
        this.myForm = formBuilder.group({
          'sku': ['', Validators.required]
        })
    }
  
    onSubmit(value) {
      console.log("you submitted value: ", value);
    }
  }
  </code></pre>
  
  <p>edited:  (@Thierry Templier)</p>
  
  <pre><code>contructor (formBuilder) {
      this.fb = formBuilder;
      this.myForm = this.fb.group({
        'sku': ['', Validators.required]
      })
    }
  
    static get parameters() {
      return [[FormBuilder]];
    }
  </code></pre>
  
  <p>my libraries:</p>
  
  <pre><code>import 'es6-shim';
  import 'reflect-metadata';
  import 'zone.js/dist/zone-microtask'
  import 'rxjs/Rx'
  import 'es6-promise'
  </code></pre>