public function load(ObjectManager $manager)
    {
        $userRole = new Role();
        $userRole->setRoleId('user');

        $manager->persist($userRole);
        $manager->flush();

        $adminRole = new Role();
        $adminRole->setRoleId('admin');
        $adminRole->setParent($userRole);

        $manager->persist($adminRole);
        $manager->flush();

        $supervisorRole = new Role();
        $supervisorRole->setRoleId('supervisor');
        $supervisorRole->setParent($userRole);

        $manager->persist($supervisorRole);
        $manager->flush();

        $gameManagerRole = new Role();
        $gameManagerRole->setRoleId('game-manager');
        $gameManagerRole->setParent($supervisorRole);

        $manager->persist($gameManagerRole);
        $manager->flush();

        // store reference to admin role for User relation to Role
        $this->addReference('admin-role', $adminRole);
        $this->addReference('supervisor-role', $supervisorRole);
        $this->addReference('game-role', $gameManagerRole);
    }