title: Symfony2 passing array to FormBuilder
body: <p>I would like to create a form which has multiple input fields corresponding to the elements of an array. In ASP.Net MVC 3 I had the ModelBuilder that encoded information about the underlying model inside the input HTML tags and rebuilt the model automatically on POST but I haven't managed to find something similar in Symfony2.<br>
  Could anyone tell me whether in Symfony2 there is a way of telling the FormBuilder that the field it receives by calling the add method is actually an array?</p>