Small bugfix

Example generally is working, except this small bug.

Author: PeterZhukov

doc/loggable.md

@@ -73,7 +73,7 @@ use Gedmo\Mapping\Annotation as Gedmo;
 use Doctrine\ORM\Mapping as ORM;
 
 /**
- * @Entity
+ * @ORM\Entity
  * @Gedmo\Loggable
  */
 class Article