title: How to generate getter setter for an jmsserializer entity
body: <p>I have made an entity to import an XML document. I use JMS serializer to decode it. So made the following Enity.</p>
  
  <pre><code>class Image
  {
      /**
       * @JMS\Type("string")
       */
      public $thumbnail_url;
  
      /**
       * @JMS\Type("string")
       */
      public $img_url;
  }
  </code></pre>
  
  <p>Now I want to generate the getter and setters around it. Normally using the following command:</p>
  
  <pre><code>app/console doctrine:generate:entities MyBundle:Image
  </code></pre>
  
  <p>Only getting the following error:</p>
  
  <blockquote>
    <p>[RuntimeException]<br>
    Namespace "MyBundle\Entity\Image" does not contain any mapped
    entities.</p>
  </blockquote>
  
  <p>How can this be solved?</p>