public async Task<ActionResult>Charge(CourseRegistrationModel model)
        {
            //if(!ModelState.IsValid)
            //{
            //    return View(model);
            //}

            var chargeId = await ProcessPayment(model, (int)TempData["courseid"] );
            Course @course = db.Courses.Find((int)TempData["courseid"]);

            var courseReg = new Course_Registration();

            foreach (var p in model.Participant)
            {
                if (p.Name != null)
                {
                    courseReg = new Course_Registration()
                    {
                        Transaction_ID = chargeId,
                        Course_ID = (int)TempData["courseid"],
                        Id = User.Identity.GetUserId(),
                        P_Name = p.Name,
                        P_Phone = p.PhoneNumber,
                        P_UnderAge = p.UnderAge
                    };
                    db.Course_Registration.Add(courseReg);
                    @course.Participating_Students++;
                    db.SaveChanges();
                }
            }          
            return View("PaymentSuccessful");
        }
        public ActionResult FreeRegistration(CourseRegistrationModel model)
        {
            var courseReg = new Course_Registration();
            Course @course = db.Courses.Find((int)TempData["courseid"]);

            foreach (var p in model.Participant)
            {
                if (p.Name != null)
                {
                    courseReg = new Course_Registration()
                    {
                        Transaction_ID = "Free Course",
                        Course_ID = (int)TempData["courseid"],
                        Id = User.Identity.GetUserId(),
                        P_Name = p.Name,
                        P_Phone = p.PhoneNumber,
                        P_UnderAge = p.UnderAge
                    };
                    db.Course_Registration.Add(courseReg);
                    @course.Participating_Students++;
                    db.SaveChanges();
                }
            }
            return View("PaymentSuccessful");
        }