Insert user_id in user_role_linker

Module.php

public function onBootstrap($e)
    {
        $app      = $e->getTarget();
        $sm       = $app->getServiceManager();
        
        $adapter = $sm->get('Zend\Db\Adapter\Adapter');

        // adding action for user registration
        $zfcServiceEvents = $sm->get('zfcuser_user_service')->getEventManager();
        $zfcServiceEvents->attach(
            'register.post', 
            function($e) use ($adapter) {
                $user = $e->getParam('user');  // User account object
                $id = $user->getId(); // get user id

                $adapter->query(
                    'INSERT INTO 
                        user_role_linker (user_id, role_id) 
                    VALUES 
                        (' . $id . ', "user")', 
                    Adapter::QUERY_MODE_EXECUTE
                );
            }
        );
    }