public ResponseModel Save(Student student)
        {
            using (SchoolManagementDBEntities db = new SchoolManagementDBEntities())
            {
                DbSet<Student> students = db.Students;
                students.Add(student);
                db.SaveChanges();

                return new ResponseModel();
            }
        }
 public ResponseModel Delete(int id)
 {
     using (SchoolManagementDBEntities db = new SchoolManagementDBEntities())
     {
         Student std = (db.Students.Where(student => student.Id == id)).FirstOrDefault();
         if (std != null)
         {
             db.Students.Remove(std);
             db.SaveChanges();
         }
         return new ResponseModel();
     }
 }