SQLAchemy No application found. Either work inside a view function or push 错误处理

refrence: https://stackoverflow.com/questions/49089584/sqlachemy-no-application-found-either-work-inside-a-view-function-or-push

key point:

app = Flask(__name__)
app.config.from_object(config)
with app.app_context():
    db.init_app(app)
    ma.init_app(app)
    db.create_all()