public void Delete(int Id)
        {
            var student = _context.Students.Where(s => s.Id == Id).FirstOrDefault();

            _context.Students.Remove(student);

            _context.SaveChanges();
        }
        public void Delete(int Id)
        {
            var teacher = _context.Teachers.Where(s => s.Id == Id).FirstOrDefault();

            _context.Teachers.Remove(teacher);

            _context.SaveChanges();
        }