我有一个适用于开发的应用程序,但是当我尝试使用Gunicorn运行它时,它会出现“sqlalchemy扩展未注册”的错误.从我所看到的,似乎我需要在某处调用app.app_context(),但我不知道在哪里.我该如何解决这个错误？

# run in development,works
python server.py

# try to run with gunicorn,fails
gunicorn --bind localhost:8000 server:app

AssertionError: The sqlalchemy extension was not registered to the current application.  Please make sure to call init_app() first.

server.py：

from flask.ext.security import Security
from database import db
from application import app
from models import Studio,user_datastore

security = Security(app,user_datastore)

if __name__ == '__main__':
    # with app.app_context(): ??
    db.init_app(app)
    app.run()

application.py：

from flask import Flask

app = Flask(__name__)
app.config.from_object('config.ProductionConfig')

database.py：

from flask.ext.sqlalchemy import sqlAlchemy
db = sqlAlchemy()