[grails] Запись в 2 таблицы одновременно

package personnel_grails

class Employee {
  String name
  String surname
  String patronymic
  Status status
  Positions positions

  static constraints = {
    surname(maxLenght: 40, blank: false)
    name(maxLenght: 40, blank: false)
    patronymic(maxLenght: 40, blank: false)
    status(nullable: false)
    positions(nullable: false)
  }
  String toString(){
    "${this.surname} ${this.name} ${this.patronymic}"
  }
}

package personnel_grails

class Positions {
    String positions
    static constraints = {
    }
  String toString(){
    "${this.positions}"
  }
}

package personnel_grails

class Status {
    String status
    static constraints = {
    }
  String toString(){
    "${this.status}"
  }
}

package personnel_grails

class Statistic {
  Employee employee
  Positions positions
  Status status
  Date date = new Date()


    static constraints = {
    }
}

    def save = {
        def employeeInstance = new Employee(params)
        if (employeeInstance.save(flush: true)) {
          def statisticInstance = new Statistic()
          statisticInstance.employee = Employee.findById(employeeInstance.id)
          statisticInstance.positions = Positions.findById(params.positions.id)
          statisticInstance.status = Status.findById(params.status.id)

          statisticInstance.save()
.....
}