Symfony2 DIC: add a Doctrine Listener Subscription

doctrine_extensions.xml

<parameters>
    <parameter key="doctrine_extensions.orm.sluggable.class">DoctrineExtensions\Sluggable\ORM\Listener</parameter>
</parameters>

<service id="doctrine_extensions.addSubscribers" class="Bundle\DoctrineExtensionsBundle\DoctrineExtensionsBundle" shared="true" factory-method="addSubscriber">
    <argument type="service" id="doctrine.dbal.default_connection.event_manager" />
    <argument type="service" id="doctrine_extensions.orm.sluggable.listener">%doctrine_extensions.orm.sluggable.class%</argument>
</service>

DoctrineExtensionsBundle.php

class DoctrineExtensionsBundle extends BaseBundle
{
    public static function addSubscriber($eventManager, EventSubscriber $subscriber)
    {
        return $eventManager->addSubscriber($subscriber);
    }
}