n.user = user

        n.user_group = user_group

        n.permission = permission

        Session().add(n)

        return n

    def __unicode__(self):

        return u'<%s => %s >' % (self.user, self.user_group)

class UserToPerm(Base, BaseModel):

    __tablename__ = 'user_to_perm'

    __table_args__ = (

        UniqueConstraint('user_id', 'permission_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    user_to_perm_id = Column("user_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    user_id = Column("user_id", Integer(), ForeignKey('users.user_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    user = relationship('User')

    permission = relationship('Permission', lazy='joined')

class UserGroupRepoToPerm(Base, BaseModel):

    __tablename__ = 'users_group_repo_to_perm'

    __table_args__ = (

        UniqueConstraint('repository_id', 'users_group_id', 'permission_id'),

        {'extend_existing': True, 'mysql_engine': 'InnoDB',

         'mysql_charset': 'utf8'}

    )

    users_group_to_perm_id = Column("users_group_to_perm_id", Integer(), nullable=False, unique=True, default=None, primary_key=True)

    users_group_id = Column("users_group_id", Integer(), ForeignKey('users_groups.users_group_id'), nullable=False, unique=None, default=None)

    permission_id = Column("permission_id", Integer(), ForeignKey('permissions.permission_id'), nullable=False, unique=None, default=None)

    repository_id = Column("repository_id", Integer(), ForeignKey('repositories.repo_id'), nullable=False, unique=None, default=None)

    users_group = relationship('UserGroup')

    permission = relationship('Permission')

    repository = relationship('Repository')

    @classmethod

    def create(cls, users_group, repository, permission):

        n = cls()

        n.users_group = users_group

        n.repository = repository

        n.permission = permission

        Session().add(n)