//GEt Vista para asignar materias al docente
        public ActionResult SubjectTeacher(string id = null)
        {
            if (id == null)
            {
                return(new HttpStatusCodeResult(HttpStatusCode.BadRequest));
            }
            Teacher teacher = db.tblTeacher.Find(id);

            if (teacher == null)
            {
                return(HttpNotFound());
            }
            else
            {
                ViewBag.subjects = subject.GetSubjects();
                return(View(teacher));
            }
        }