title: Symfony form handleRequest not populating
body: <p>I have a symfony 3 form. And I'm trying to populate it with handleRequest like this:</p>
  
  <pre><code>$user = new User();
  $userForm = $this-&gt;createForm(UserType::class, $user);
  print_r($request-&gt;request-&gt;all());
  $userForm-&gt;handleRequest($request);
  
  print_r($userForm-&gt;getData());
  </code></pre>
  
  <p>The output I get is:</p>
  
  <pre><code>Array
  (
      [firstName] =&gt; test
      [last_name] =&gt; test
      [email] =&gt; test@test.test
      [password] =&gt; erkeferke
      [gender] =&gt; F
      [supervisor] =&gt; 1
  )
  AppBundle\Entity\User Object
  (
      [id:AppBundle\Entity\User:private] =&gt; 
      [firstName] =&gt; 
      [lastName:AppBundle\Entity\User:private] =&gt; 
      [email:AppBundle\Entity\User:private] =&gt; 
      [password:AppBundle\Entity\User:private] =&gt; 
      [photo:AppBundle\Entity\User:private] =&gt; 
      [gender:AppBundle\Entity\User:private] =&gt; 
      [supervisor:AppBundle\Entity\User:private] =&gt; 
      [duties:AppBundle\Entity\User:private] =&gt; 
      [lastLogin:AppBundle\Entity\User:private] =&gt; 
      [createdAt:AppBundle\Entity\User:private] =&gt; 
      [updatedAt:AppBundle\Entity\User:private] =&gt; 
      [deletedAt:AppBundle\Entity\User:private] =&gt; 
  )
  </code></pre>
  
  <p>Any idea why it's not populating?</p>