Test against Rails 4.0 (with beta versions of Mongoid/MongoMapper)
Fix MongoidStore for Mongoid 4 while remaining Mongoid 3 compatible.
Test against Rails 4.1.0.rc1
README: Drop "Performance" section.

Very old numbers. Haven't bothered to run new ones.
Rake tasks for running each combo of Rails and ORM
Double gemspecs!
README update with changelog
Don't set the database automatically for the MongoStore.

Wasn't tested. Hard to test in current setup.
Version Bump 5.0.0.