public ActionResult BatchObservationDetails(BatchObservationViewModel model)
        {
            var observation = mapper.Map <BatchObservationViewModel, Observation>(model);
            var results     = gameEngine.BatchCreateObservations(observation, model.Users);

            PrepareBatchObservationViewModel(model);
            ViewData["Message"] =
                $"Successfully created {results.Succeeded}; Failed to create {results.Failed} observations.";

            foreach (var key in results.Errors.Keys)
            {
                ModelState.AddModelError(null, $"{key}: {results.Errors[key]}");
            }
            return(View(model));
        }