public ActionResult AddLanguageToPerson(PersonLanguageViewModel personLanguageViewModel)
        {
            if (ModelState.IsValid)
            {
                var personID   = personLanguageViewModel.Person.Id;
                var languageID = personLanguageViewModel.Language.Id;

                var existingItems = _context.PersonLanguage
                                    .Where(pl => pl.PersonID == personID)
                                    .Where(pl => pl.LanguageID == languageID).ToList();

                if (existingItems.Count == 0)
                {
                    PersonLanguage newItem = new PersonLanguage
                    {
                        Person   = _context.People.Single(p => p.Id == personID),
                        Language = _context.Language.Single(l => l.Id == languageID)
                    };

                    _context.PersonLanguage.Add(newItem);
                    _context.SaveChanges();
                }
                return(RedirectToAction(nameof(Index)));
            }
            return(RedirectToAction(nameof(Index)));
        }
        public ActionResult AddLanguageToPerson()
        {
            PersonLanguageViewModel personLanguageViewModel = new PersonLanguageViewModel();
            //PeopleViewModel peopleViewModel = new PeopleViewModel();

            var resultPeopleViewModel = _peopleService.All();

            personLanguageViewModel.PeopleList   = resultPeopleViewModel.PersonList;
            personLanguageViewModel.LanguageList = _languageService.All();

            return(View(personLanguageViewModel));
        }