Feature Request: celery support

[rmelick-vida]

In our application, a lot of our database load comes from scheduled celery tasks. They still use the Django ORM to access the database. Since they're coming from celery however, they don't go through the Middleware chain, so the queries aren't getting annotated by the google.cloud.sqlcommenter.django.middleware.SqlCommenter middleware.

Are there any suggestions on how to integrate sqlcommenter in with celery?