DatabaseCleaner/database_cleaner — pull request #278 by Imomoi (2014-06-20 12:17:41+00:00)
Title: Updated regexp for filter system collections

Now it's possible to clean collections with names like:

favourite_systems
operating_systems
systems

and so on.

All real mongo's system collections have following name format (as in 2.4.1):

{db_name}.system.{system_collection_type}