private void Execute(DeleteUser command)
        {
            var user = AggregateStore.GetAggregate <User>(command.Id);

            user.Delete();
            AggregateStore.Save(user);
        }
        private void Execute(ChangeUser command)
        {
            var user = AggregateStore.GetAggregate <User>(command.Id);

            user.Change(command.Name, command.EMail, command.Password);
            AggregateStore.Save(user);
        }