title: Is it possible to add property dynamically to groupform
body: <p>Is it possible to add property dynamically to groupform? 
  I need a property name to have an index as part of the name </p>
  
  <pre><code>createForm() {
      for (let index = 0; index &lt; 10; index++) {
          this.groupForm = this.fb.group({
              prixName+index: ['', [Validators.maxLength(4)]],
          });
  
  
      }
  }
  </code></pre>