public ActionResult Operation(string submitButton, AddWorkerModel model)
        {
            switch (submitButton)
            {
            case "Add":
                // delegate sending to another controller action
                if (ModelState.IsValid)
                {
                    _es.GetHumanDepartment().AddNewWorker(new Worker(model.addName, model.addSecondName, model.age, model.monthsWorkedOut, model.position, model.passport));
                }

                return(RedirectToAction("Index"));

            case "Remove":
                _es.GetHumanDepartment().RemoveWithpassport(model.passport);

                return(RedirectToAction("Index"));

            case "Update":
                _es.GetHumanDepartment().UpdateWorkedOutHours(new Worker(model.addName, model.addSecondName, model.age, model.monthsWorkedOut, model.position, model.passport));

                return(RedirectToAction("Index"));

            default:
                return(View());
            }
        }