Add option to disable mview sync

[Qu4tro]

No description provided.

[rhngit]

lgtm; we have one normal view right now, right?

[Qu4tro]

Yes. Unless you count #412, then we have 3.

[amackie-zyper]

Our previous change to this fork was a modification to completely disable post-migration sync of everything. Why not bring this back with some kind of Django settings based option to decide what kind of views get synced on startup?

Or possibly more generally what ViewSyncer.run() does? That way we don't need to worry about changing deployment steps either

[Qu4tro]

I guess that makes sense, but I'm not sure where sync_pgviews from apps is called.

We would then have a test setting to migrate everything and a production setting to avoid materialized views. Was that what were you thinking?

[amackie-zyper]

So it's been commented out here in this commit: 70ca721#diff-3298f2c0a31d05260003b7d38be4dbdcR45

My thought was that something would check django.settings for something like PGVIEWS_STARTUP_SYNC which would have a list like ['views', 'materialized_views'], which we would set to ['views'] in zyper-django-api, and its the same for test and production. Mviews carry on having to have a specific migration for them. (I'm really not keen on any difference between local, test & prod in this way)

Also, I hope we have a better chance of upstreaming if we can make this optional. To that end, if we take this route it might be best to get this fork up to date and discard the old commits.