users_group_id = Column(Integer(), primary_key=True)

    users_group_name = Column(Unicode(255), nullable=False, unique=True)

    user_group_description = Column(Unicode(10000), nullable=True) # FIXME: not nullable?

    users_group_active = Column(Boolean(), nullable=False)

    owner_id = Column('user_id', Integer(), ForeignKey('users.user_id'), nullable=False)

    created_on = Column(DateTime(timezone=False), nullable=False, default=datetime.datetime.now)

    _group_data = Column("group_data", LargeBinary(), nullable=True)  # JSON data # FIXME: not nullable?

    members = relationship('UserGroupMember', cascade="all, delete-orphan")

    users_group_to_perm = relationship('UserGroupToPerm', cascade='all')

    users_group_repo_to_perm = relationship('UserGroupRepoToPerm', cascade='all')

    users_group_repo_group_to_perm = relationship('UserGroupRepoGroupToPerm', cascade='all')

    owner = relationship('User')

    @hybrid_property

    def group_data(self):

        if not self._group_data:

            return {}

        try:

            return ext_json.loads(self._group_data)

        except TypeError:

            return {}