title: Get value of a field not declared in FormType
body: <p>I have a form declared in <code>nameType.php</code> and the view render all field but I want add another field manually.</p>
  
  <p>Form:</p>
  
  <pre><code>&lt;form action="{{ path('create') }}" method="post" {{ form_enctype(form) }}&gt;
      {{ form_widget(form) }}
      &lt;input type="text" value="2"&gt;
     &lt;/form&gt;
  </code></pre>
  
  <p>And get the values in the controller:</p>
  
  <pre><code>$form-&gt;bindRequest($request);
  </code></pre>
  
  <p>How can I collect the value of the input in the controller?</p>