/// <summary>
        /// Opens the new watchlist.
        /// </summary>
        /// <param name="userId">The unique identifier of the user who owns the watchlist.</param>
        /// <param name="name">The watchlist name.</param>
        /// <param name="symbols">The initial symbols on the watchlist.</param>
        /// <returns>The identifier of the newly created watchlist.</returns>
        public Guid CreateWatchlist(Guid userId, string name, IEnumerable <string> symbols)
        {
            Validate.NotEmpty(userId, nameof(userId));
            Validate.NotNullOrWhitespace(name, nameof(name));

            Watchlist watchlist = Watchlist.CreateNew(userId, name, symbols);

            _watchlistRepository.Save(watchlist);
            return(watchlist.Id);
        }
        public IActionResult New(int petId)
        {
            try{
                string UserId = _userManager.GetUserId(HttpContext.User);

                Watchlist watchlist = new Watchlist();
                watchlist.PetId = petId;

                watchlist.UserId = UserId;

                if (!_repository.IsWatchlistExists(petId, UserId))
                {
                    _repository.Save(watchlist);
                }
                else
                {
                    return(Content("Already exists in your watchlists"));
                }
                return(RedirectToAction(nameof(Index)));
            } catch (Exception ex) {
                throw ex;
            }
        }