private void createReservationData() {
EntityManager entityManager = entityManagerFactory.createEntityManager();
entityManager.getTransaction().begin();
entityManager.persist(new Reservation(
entityManager.find(Reader.class, 1l),
entityManager.find(Book.class, 8l),
new Date(System.currentTimeMillis())));
entityManager.persist(new Reservation(
entityManager.find(Reader.class, 1l),
entityManager.find(Book.class, 9l),
new Date(System.currentTimeMillis())));
entityManager.getTransaction().commit();