static async Task RegisterCustomers()
        {
            using (var context = new FinancesContext())
            {
                var customers = GetCustomers();

                foreach (var customer in customers)
                {
                    await context.Customers.AddAsync(customer);
                }

                await context.SaveChangesAsync();
            }
        }
 public async Task AddAsync(User user)
 {
     await _context.Users.AddAsync(user);
     await _context.SaveChangesAsync();
 }