mongoid/mongoid — pull request #3125 by CodeMonkeySteve (2013-06-24 22:19:50+00:00)
Title: Create indexes in background by default.

For safety, all indexes should be created in the background by default (in my opinion). I forgot to include "background: true" on an index spec, which just caused our production website to go down while the DB created the index. Would very much like that to never happen again.