public void HandOver(TransferItemModel model,
     Role role, int succesorId, int operaterId)
 {
     throw new NotImplementedException();
 }
        public void HandOver(TransferItemModel model,
            Role role, int succesorId, int operaterId)
        {
            Task task = session.Load<Task>(model.Id);
            User successor = session.Load<User>(succesorId);
            User operater = session.Load<User>(operaterId);

            switch (role)
            {
                case Role.Publisher:
                    task.ChangePublisher(operater, successor);
                    break;
                case Role.Owner:
                    task.ChangeOwner(operater, successor);
                    break;
                case Role.Accepter:
                    task.ChangeAccepter(operater, successor);
                    break;
            }

        }