Rails 3 compatible version

This version of the script works with Rails 3. I made it the master branch, and moved the previous version to a branch called rails2-log-format. Since Rails 2 is no longer supported, I felt this made sense.

Please feel free to reject this pull request if you will not find these changes useful. I have removed the before/after context, which might be important to you, but I plan to re-implement this in the future.