title: Injecting a service into an entity
body: <p>I have an entity called <code>Container</code> which depends on a service, <code>DeviceService</code>. </p>
  
  <p>I currently inject it using an <em>Entity Listener</em> on <em>postLoad</em>. However this is not being injected when just creating the plain object <code>new Container()</code>. </p>
  
  <p>Should I create a <code>ContainerFactory</code> where I inject the service into the new object, along with the current listener, or do a smarter way exist in Symfony?</p>