class User(Base):
    __tablename__ = 'users'

    id = Column(String(20), primary_key=True)
    name = Column(String(15), nullable=False)
    full_name = Column(Text)
    description = Column(Text)
    created = Column(DateTime)
    location = Column(Text)
    protected = Column(Boolean)

    followers_count = Column(Integer)
    friends_count = Column(Integer)
    favourites_count = Column(Integer)
    statuses_count = Column(Integer)
    listed_count = Column(Integer)

    imported = Column(DateTime(timezone=True), default=func.now())
    updated = Column(DateTime(timezone=True), onupdate=func.now())

    tags = Column(ARRAY(Text), nullable=False,
        default=cast(array([], type_=Text), ARRAY(Text)))

    followers = relationship('User', secondary=follows,
        primaryjoin=id == follows.c.to_id,
        secondaryjoin=id == follows.c.from_id,
        order_by=follows.c.id,
        backref='friends', lazy='subquery')

    tweets = relationship('Tweet',
        primaryjoin='User.id == foreign(Tweet.user_id)',
        backref='user', lazy='subquery', viewonly=True)

    __table_args__ = (
        Index('ix_user_name_lower', func.lower('name')),
        Index('ix_user_tags', tags, postgresql_using='gin'),
    )