Pulp

Once we switch fully to mongoengine, we can get rid of the dumb thing
that drops the index with each pulp-manage-db.

Once we've done that, my preference would be for us to stop dropping the
indices in pulp-manage-db, and leave it to the user to use the Mongo
shell to add their own custom indices.

Some users want the ability to search on a particular field of a particular collection frequently, and thus need the ability to define custom indexes. Right now, pulp will destroy user-defined indexes when pulp-manage-db runs.

Deliverables:

• move the drop and create indexes code from pulp-manage-db into a new migration
• add a release note that only after running pulp-manage-db one last time will the user's indexes are now safe to be added and they will not be dropped
• add a note in the user facing docs that users are free to add/manage their own migrations on mongodb
• add a section to the developer docs that explains a migration needs to be used for deletion of indexes in the future