public ActionResult BookActivity(int activityId = 0)
 {
     var activity = db.Activities.FirstOrDefault(a => a.Id == activityId);
     var activityBooking = new ActivityBooking()
     {
         Activity = activity,
         Customer = new Customer(),
         Note = "",
     };
     return View(activityBooking);
 }
        public ActionResult BookActivity(ActivityBooking activityBooking)
        {
            var a = activityBooking;

            db.Bookings.Add(new Booking()
            {
                ActivityId = activityBooking.Activity.Id,
                Note = activityBooking.Note,
                Customer = activityBooking.Customer,
            });
            db.SaveChanges();

            return RedirectToAction("ViewWeek", "Calender", new { id = activityBooking.Activity.CalenderId, activityDate = activityBooking.Activity.Date.ToShortDateString() });
        }