readme is not correct

[allan-simon]

    $cardRegistration = new CardRegistration();
    $this->get('troopers_mangopay.payment_helper')->createPreAuthorisation($cardRegistration);

as createPreAuthorization does not take a cardRegistration, i guess you meant:

 $this->get('troopers_mangopay.card_registration_helper')->createCardRegistrationForUser($user);