public IEnumerable <DeliveryViewModel> GetDeliveriesForUser(string username)
{
if (username == null)
{
throw new ArgumentNullException(nameof(username), "Recepient is null");
}
var user = GetUser(username);
if (user == null)
{
throw new InvalidOperationException("User cannot be found");
}
return(_deliveryRepository.GetByUsername(user.Username).Select(d => d.ToDeliveryViewModel()));
}