public int Create(SellingItem item)
        {
            this.items.Add(item);

            this.items.Save();

            return item.Id;
        }
        public void Update(int id, SellingItem item)
        {
            var entityToUpdate = this.items.GetById(id);

            entityToUpdate.Title = item.Title;
            entityToUpdate.Description = item.Description;
            entityToUpdate.PriceBGN = item.PriceBGN;
            entityToUpdate.Availability = item.Availability;
            entityToUpdate.Images = item.Images;

            this.items.Save();
        }
        public int Create(string title, string description, string sellerId, decimal price, int availability)
        {
            var newEntity = new SellingItem()
            {
                Title = title,
                Description = description,
                SellerId = sellerId,
                PriceBGN = price,
                Availability = availability
            };

            this.items.Add(newEntity);

            this.items.Save();

            return newEntity.Id;
        }