public IHttpActionResult Post(Guid companyId, Guid signboardId, ScheduledSlideshowModel model)
        {
            var signboard = SignboardRepository.Find(signboardId);

            if (signboard == null)
            {
                return NotFound();
            }

            if (signboard.CompanyId != companyId)
            {
                return NotFound();
            }

            var scheduledSlideshow = SlideshowRepository.Find(model.SlideshowId);

            if (scheduledSlideshow == null)
            {
                return BadRequest();
            }

            signboard.ScheduleSlideshow(scheduledSlideshow, model.StartDate);
            SignboardRepository.Update(signboard);

            return Created(new Uri(Url.Link("GetScheduledSlideshow", new { signboardId = signboard.Id, companyId = signboard.CompanyId, scheduledSlideshowId = scheduledSlideshow.Id })), model);
        }
        public IHttpActionResult Get(Guid companyId, Guid signboardId, Guid scheduledSlideshowId)
        {
            var signboard = SignboardRepository.Find(signboardId);

            if (signboard == null)
            {
                return NotFound();
            }

            if (signboard.CompanyId != companyId)
            {
                return NotFound();
            }

            var scheduledSlideshow = signboard.ScheduledSlideshows.SingleOrDefault(x => x.Id == scheduledSlideshowId);

            if (scheduledSlideshow == null)
            {
                return NotFound();
            }

            var responseModel = new ScheduledSlideshowModel()
            {
                ScheduledSlideshowId = scheduledSlideshow.Id,
                StartDate = scheduledSlideshow.ScheduledDate,
                SlideshowId = scheduledSlideshow.SlideshowId
            };

            return Ok(responseModel);
        }