public function drop()
 {
     $driver = $this->em->getConfiguration()->getMetadataDriverImpl();
     $entities_names = $driver->getAllClassNames();
     $entities_metadata = array();
     foreach ($entities_names as $name) {
         array_push($entities_metadata, $this->em->getClassMetadata($name));
     }
     $tool = new \Doctrine\ORM\Tools\SchemaTool($this->em);
     $tool->DropSchema($entities_metadata);
 }