public IActionResult SaveEntity(EpisodeViewModel vm)
 {
     if (!ModelState.IsValid)
     {
         IEnumerable <ModelError> allErrors = ModelState.Values.SelectMany(v => v.Errors);
         return(new BadRequestObjectResult(allErrors));
     }
     else
     {
         if (vm.Id == 0)
         {
             _episodeService.Add(vm);
         }
         else
         {
             _episodeService.Update(vm);
         }
         return(new OkObjectResult(vm));
     }
 }