Using select2 for reason field inside activity form

src/Bundle/ChillActivityBundle/Form/ActivityType.php

@@ -188,6 +188,7 @@ class ActivityType extends AbstractType
                 'choice_label' => function (ActivityReason $activityReason) {
                     return $this->translatableStringHelper->localize($activityReason->getName());
                 },
+                'attr' => array('class' => 'select2 '),
                 'query_builder' => function (EntityRepository $er) {
                     return $er->createQueryBuilder('a')
                         ->where('a.active = true');