init.py

# é equivalente ao app, dentro da pasta app

from flask import Flask
from flask_migrate import Migrate
from app.models.models import db
from config import app_config
import os

migrate = Migrate()
config_name = os.environ.get('FLASK_CONFIG')

def create_app(config_filename='config.py', config_name=config_name):   #app factory
    app = Flask('teste', template_folder='app/templates')
    app.config.from_object(app_config[config_name])
    db.init_app(app)
    migrate.init_app(app,db)

    return app