title: Set default value on Datetime field in symfony2 form
body: <p>I have a form containing several fields. One of them is a Datetime field. How to define a default value for that field? </p>
  
  <p>I've tried setting a value on the related entity, in controller, in constructor and __construct :</p>
  
  <pre><code>$myEntity = new MyEntity();
  $myEntity-&gt;setMyDate(new \DateTime());
  $form = $this-&gt;createForm(new AddMyEntity(), $myEntity);
  </code></pre>
  
  <p>Not working. </p>
  
  <p>Tried to define the <code>$data</code> variable in the buildForm : </p>
  
  <pre><code>$builder-&gt;add('myDate', 'date', array(
      'format' =&gt; \IntlDateFormatter::SHORT,
      'input' =&gt; 'datetime',
      'widget' =&gt; 'single_text',
      'data' =&gt; new \DateTime("now"));
  </code></pre>
  
  <p>Not working either. 
  Any ideas, Symfony2 community?</p>
  
  <p>EDIT : Adding entity on demand of faost. </p>
  
  <pre><code>/**
   * @ORM\Column(name="myDate", type="datetime")
   * @Assert\NotBlank()
   */
  private $myDate;
  </code></pre>