title: How to allow a checkbox to be empty in symfony?
body: <p>I have defined the following variable within an entity in my application. I have this, among other fields that can be updated via a form interface and I wish to be able to check and uncheck this box on that form.</p>
  
  <p>I can check the box and submit the form fine, but it seems that when I uncheck the box, I can't submit the form. It gives me a <code>Please check this box if you want to proceed</code>.</p>
  
  <pre><code>/**
   * @var boolean $updatesNeeded
   *
   * @ORM\Column(name="updates_needed", type="boolean", nullable=false)
   */
  private $updatesNeeded;
  </code></pre>
  
  <p>I tried changing <code>nullable=false</code> to <code>nullable=true</code> and updating the schema, but it doesn't seem to work. Any ideas would be much appreciated.</p>
  
  <pre><code>use Symfony\Component\Form\AbstractType;
  use Symfony\Component\Form\FormBuilder;
  
  class BlahType extends AbstractType
  {
      /**
       * @param \Symfony\Component\Form\FormBuilder $builder
       * @param array                               $options
       */
      public function buildForm(FormBuilder $builder, array $options)
      {
          $builder
              -&gt;add('stuff')
              -&gt;add('updatesNeeded', 'choice', array('required' =&gt; false))
              -&gt;add('anothervar');
      }
  }
  </code></pre>