manage.py

import os
from flask import Flask
from flask_migrate import Migrate, MigrateCommand, init, migrate, upgrade
from flask_script import Manager

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

from db import (
    DB_NAME,
    DB_HOST,
    DB_PASS,
    DB_USER,
    DB_PORT,
)

app = Flask(__name__)
app.config[
    "SQLALCHEMY_DATABASE_URI"
] = f"postgresql+psycopg2://{DB_USER}:{DB_PASS}@{DB_HOST}:{DB_PORT}/{DB_NAME}"
app.config["SQLALCHEMY_COMMIT_ON_TEARDOWN"] = True
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = True

db.init_app(app)
migrate_app = Migrate(app, db)

manager = Manager(app)
manager.add_command("db", MigrateCommand)

if __name__ == "__main__":
    manager.run()