public ActionResult DeleteActivity(int id)
        {
            Activity dbActivity = activitiesService.GetById(id);

            if (dbActivity == null)
            {
                TempData["ErrorMessage"] = "There is no existing activity with that id";
                return(RedirectToAction("ViewActivities", "Activities"));
            }

            bool hasSuccessfullySaved = activitiesService.Delete(dbActivity);

            if (hasSuccessfullySaved)
            {
                TempData["SuccessfullMessage"] = "Activity successfully deleted";
                return(RedirectToAction("ViewActivities", "Activities"));
            }
            else
            {
                TempData["ErrorMessage"] = "Server error during the activity deletion";
                return(RedirectToAction("ViewActivities", "Activities"));
            }
        }