Viral queue waitlist and referrals

models.py

class Waitlist(BaseModel, db.Model):
    __tablename__ = 'waitlist'

    initial_score = 65231
    decrease_per_referral = 10

    uuid = db.Column(db.String(8), primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'))
    user = db.relationship('User', back_populates='waitlist')
    score = db.Column(db.Integer)
    referred = db.relationship(
        'Waitlist',
        secondary=referrals,
        primaryjoin=(referrals.c.referring == uuid),
        secondaryjoin=(referrals.c.referred == uuid),
        backref=db.backref('referral', lazy='dynamic'), lazy='dynamic')

    def __init__(self, user_id):
        self.user_id = user_id
        self.set_uuid()
        self.set_initial_score()

    def set_uuid(self):
        uuid = utils.generate_simple_uuid(8)
        while db.session.query(Waitlist).filter_by(uuid=uuid).one_or_none():
            uuid = utils.generate_simple_uuid(8)
        self.uuid = uuid

    def set_initial_score(self):
        self.score = self.initial_score + db.session.query(Waitlist).count() + 1