In 2.6 we'll have customizable roles, and so not every user who will be able to insert documents into a GridFS bucket will have permission to create the prerequisite unique index on

.

Proposed fix: add a createGridFS bucket command, so that admins can give users the ability to create GridFS buckets without having privileges to build indexes generally.

Driver changes needed: drivers should be changed to use createGridFS, then maybe fail over to trying the ensureIndex. (Eventually, the ensureIndex call could be dropped from drivers, too.)

Docs changes needed: document the new command, maybe add a release note that taking away createIndex from a user will require upgrading drivers in order to use GridFS.

Tools changes needed: mongofiles, I guess.