Handle indexes ourselves instead of via mongokit

[Christopher Allan Webber]

See:
`https://groups.google.com/group/mongokit/browse\_thread/thread/50c0c9ab4a313010 <https://groups.google.com/group/mongokit/browse_thread/thread/50c0c9ab4a313010>`_

It looks like the indexes feature in mongokit is acknowledged as
not well implemented for production. We should figure out a nice
way of doing this ourselves, possibly via a command to ./bin/gmg
and then adding / removing indexes later via migrations?

Alternately we could keep some value in the database about whether
indexes have **ever** been set up, and if not, set up the current
indexes, and then handle all subsequent ones via migrations? We
don't want it to be hard to have new users have migrations from the
get-go without having to run an extra command, maybe.

[Christopher Allan Webber]

Alternately 0.7.0 could come out and solve this for us ;)

I think it's fine for tickets to not block on this and use the
index feature of mongokit until we figure this out though.

[Christopher Allan Webber]

Horray! I did this and merged it into master and pushed that code.
See the mediagoblin/db/indexes.py for more information, but
basically if you run ./bin/gmg migrate it should update the indexes
for you also.

[Will Kahn-Greene]

The original url for this bug was ​http://bugs.foocorp.net/issues/342 .