Create celery app in flask-app context

celery.py

from celery import Celery
from app import create_app

def create_celery_app(app=None):
	app = app or create_app('default')
	celery = Celery(__name__, broker=app.config['CELERY_BROKER_URL'])
	celery.conf.update(app.config)
	Taskbase = celery.Task

	class ContextTask(Taskbase):
		abstract = True

		def __call__(self, *args, **kwargs):
			with app.app_context():
				return Taskbase.__call__(self, *args, **kwargs)
	
	celery.Task = ContextTask
	return celery