public IActionResult GetStudents(string orderBy)
        {
            //return "Kowalski, Malewski, Andrzejewski";
            var service = new MockDbServices();

            return(Ok(service.GetStudents()));
        }
        public IActionResult Put(int id)
        {
            var service = new MockDbServices();
            var stud    = service.GetStudents().Where(s => s.IdStudent == id).FirstOrDefault <Student>();

            stud.IndexNumber = "2222";
            return(Ok("Aktualizacja ukonczona"));
        }