models.py

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class User(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(80), unique=True, nullable=False)
    password = db.Column(db.String(120), nullable=False)

    feedbacks = db.relationship('Feedback', backref='user', lazy=True)

class Feedback(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    feedback = db.Column(db.Text, nullable=False)
    
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)