Hi,

I can't find a change log for the ruby gems (the driver and bson_ext).
If there is one, it might be a good head to put it in a "standard" place, like a CHANGELOG text file at the root of the project.
If not, it would be great to make one for future version because sometimes a test suite is not enough to decide if an upgrade is possible or even worth the effort.

Thanks for the great work.