BlogBundle/Twig/BlogExtension.php
public function getCategories()
    {
        $em = $this->container->get('doctrine')->getManager();
        $entities = $em->getRepository('BlogBundle:Category')->findBy(array('active' => true),array('name' =>  'ASC'));
        
        return $entities;
    }
public function getCategories()
    {
        $em = $this->container->get('doctrine')->getManager();
        $entities = $em->getRepository('BlogBundle:Category')->findBy(array('active' => true),array('name' =>  'ASC'));
        
        return $entities;
    }
Returns array tags

@param object $tag