addRole using userManager doesn't work

I'm trying to add roles to user when they are registering in this way:

$em = $this->getDoctrine()->getManager();

$userManager = $this->container->get('fos_user.user_manager');
$user = $userManager->createUser();

$user_data = $request->get('user_profile');

$user->setUsername($user_data['rif']);
$user->setEmail($user_data['user']['email']);
$user->setPlainPassword($user_data['user']['password']);
$user->addRole("ROLE_USER");
$userManager->updateUser($user);

All works fine excepts that roles at DB is stored as a:0:{} and I can't find the error, can any give me some advice on this?

I think your problem is that you are trying to add the ROLE_USER role.

Have you tried adding another role?

The problem lies in..

FOS\UserBundle\Model\UserInterface

const ROLE_DEFAULT = 'ROLE_USER';
const ROLE_SUPER_ADMIN = 'ROLE_SUPER_ADMIN';

FOS\UserBundle\Model\User

public function addRole($role)
{
    $role = strtoupper($role);
    if ($role === static::ROLE_DEFAULT) {
    // If supplied $role === ROLE_USER just return User object
        return $this;
    }

    if (!in_array($role, $this->roles, true)) {
        $this->roles[] = $role;
    }

    return $this;
}

....

/**
 * Returns the user roles
 *
 * @return array The roles
 */
public function getRoles()
{
    $roles = $this->roles;

    foreach ($this->getGroups() as $group) {
        $roles = array_merge($roles, $group->getRoles());
    }

    // we need to make sure to have at least one role
    $roles[] = static::ROLE_DEFAULT;

    return array_unique($roles);
}

If you add the default role (ROLE_USER) it doesn't actually get added to the list of roles due to it being added, as default, to the roles in the getRoles method.