Parent form type

VideoType.php

public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $modelTransformer = new TagsTransformer($this->manager);
        $tags = $this->manager->getRepository('ForaSoftImproveClassBundle:Tag')->findAll();
        $builder->add(
            $builder->create('tags', 'genemu_jqueryselect2_hidden', array(
                'configs' => array(
                    'tags' => $modelTransformer->extractStrings($tags),
                    'tokenSeparators' => array(' ', ',', ';'),
                ),
            ))->addModelTransformer($modelTransformer)
        );
    }