class Subscriber(db.Model):

    user_id = db.Column(db.Integer, primary_key=true)

    client_id = ....

    ....

​

    # method to add new subscriber

    def __init__(self, user_id, client_id)

        self.user_id = user_id

        self.client_id = client_id

​

@app.route('/subscribe/')

def subscribe():

    # add a subscriber with user id 21, client 543

    new = Subscriber(21, 543)

    db.session.add(new)

    db.session.commit()

​

@app.route('/unsubscribe/')

def unsubscribe():

    # remove subscriber

    Subscriber.query.filter_by(user_id=21, client_id=543).delete()

    db.session.commit()