Fatal error: Uncaught Error: Interface 'Symfony\Component\Form\DataTransformerInterface' not found in /home/lafaamicps/www/symfony/vendor/friendsofsymfony/user-bundle/FOS/UserBundle/Form/DataTransformer/UserToUsernameTransformer.php:15 Stack trace: #0 {main} thrown in /home/lafaamicps/www/symfony/vendor/friendsofsymfony/user-bundle/FOS/UserBundle/Form/DataTransformer/UserToUsernameTransformer.php on line 15