public void updateFrostyRegistration(WebFrostyRegistration webRegistration)
        {
            // Check if registration is enabled for this event occurrence.
            EventOccurrence eventOccurrence = db.EventOccurrences
                .SingleOrDefault(e => e.id == webRegistration.eventOccurrenceId);
            if (eventOccurrence != null)
            {
                if (!eventOccurrence.isActive)
                {
                    throw new Exception("You cannot register for this event because it is not active");
                }
                FrostyRegistration registration = db.FrostyRegistrations
                    .SingleOrDefault(r => r.id == webRegistration.id);
                if (registration != null && (registration.userId == me.id || me.type == "admin"))
                {
                    registration.eventOccurrenceId = webRegistration.eventOccurrenceId;
                    // Only allow admins to manually mark registration as being paid (e.g. in person with cash/check).
                    if (me.type == "admin")
                    {
                        registration.isPaid = webRegistration.isPaid;
                    }
                    registration.isMinor = webRegistration.isMinor;

                    db.SaveChanges();
                }
                else
                {
                    throw new PermissionDeniedException();
                }
            }
            else
            {
                throw new PermissionDeniedException();
            }
        }
        public int addFrostyRegistration(WebFrostyRegistration webRegistration)
        {
            // Check if registration is enabled for this event occurrence.
            EventOccurrence eventOccurrence = db.EventOccurrences
                .SingleOrDefault(e => e.id == webRegistration.eventOccurrenceId);
            if (eventOccurrence != null)
            {
                if (!eventOccurrence.isActive)
                {
                    throw new Exception("You cannot register for this event because it is not active");
                }
                FrostyRegistration registration = new FrostyRegistration();
                registration.eventOccurrenceId = webRegistration.eventOccurrenceId;
                registration.userId = this.me.id;
                registration.isPaid = false;
                registration.isMinor = webRegistration.isMinor;
                registration.dateCreated = DateTime.UtcNow;

                db.FrostyRegistrations.Add(registration);
                db.SaveChanges();

                return registration.id;
            }
            else
            {
                throw new PermissionDeniedException();
            }
        }
        public HttpResponseMessage Post(WebFrostyRegistration registration)
        {
            if (!ModelState.IsValid || registration == null)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest, ModelState);
            }

            try
            {
                int id = repo.addFrostyRegistration(registration);
                return Request.CreateResponse(HttpStatusCode.Created, id);
            }
            catch (Exception e)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest, e);
            }
        }
        public HttpResponseMessage Put(int id, WebFrostyRegistration registration)
        {
            if (!ModelState.IsValid || registration == null || id != registration.id)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest, ModelState);
            }

            try
            {
                repo.updateFrostyRegistration(registration);
                return Request.CreateResponse(HttpStatusCode.OK);
            }
            catch (Exception e)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest, e);
            }
        }