public async Task <Order> Save(Order order)
        {
            await _context.Set <Order>().AddAsync(order);

            await _context.SaveChangesAsync();

            return(order);
        }
        public async Task <Product> Save(Product product)
        {
            await _context.Set <Product>().AddAsync(product);

            await _context.SaveChangesAsync();

            return(product);
        }
        public async Task <Client> Save(Client client)
        {
            await _context.Set <Client>().AddAsync(client);

            await _context.SaveChangesAsync();

            return(client);
        }