models.py

from flask_sqlalchemy import SQLAlchemy
from flask_login import UserMixin

db = SQLAlchemy()

class User(db.Model, UserMixin):
    id = db.Column(db.Integer, primary_key=True)
    username = db.Column(db.String(150), nullable=False, unique=True)
    password = db.Column(db.String(150), nullable=False)
    achievements = db.relationship('Achievement', backref='user', lazy=True)

class Achievement(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    title = db.Column(db.String(100), nullable=False)
    description = db.Column(db.String(255), nullable=False)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)

class Progress(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    user_id = db.Column(db.Integer, db.ForeignKey('user.id'), nullable=False)
    course_id = db.Column(db.Integer, nullable=False)
    completed = db.Column(db.Boolean, default=False)