code: public static JpaModule createServerModule(JpaModuleConfig config, EntityManager em, TransactionRunner transactionRunner) {
          return createServerModule(config, () -> em, transactionRunner);
      }
docs: Creates a new JpaModule for a Crnk server. No entities are by
  default exposed as JSON API resources. Make use of
  {@link #addRepository(JpaRepositoryConfig)} to add resources.
  
  @param em                to use
  @param transactionRunner to use
  @return created module