ref: (Django 1.9) Replace `pre_syncdb` with `pre_migrate`
ref: (Django 1.9) Replace `pre_syncdb` with `pre_migrate`

`pre_syncdb` was deprecated in 1.7, and is now removed in 1.9.
https://docs.djangoproject.com/en/2.2/releases/1.7/#schema-migrations

mvaled/sentry,mvaled/sentry,mvaled/sentry,mvaled/sentry,mvaled/sentry,beeftornado/sentry,beeftornado/sentry,mvaled/sentry,beeftornado/sentry