ActiveRecord::Base.class_eval not being called

I am extending activerecord to write some audit data before each save or
create using this in the environment.rb file:

ActiveRecord::Base.class_eval do
blah
blah
blah
end

It was working the first day I did this, and now it has stopped. I tried
backing out of any changes that could have been made in the mean-time,
but to no avail.

if I put a logger.debug in the method, I see that it gets hit each time
the ap is started, but never after.

Any ideas why activerecord is not seeing this extension?

Thanks

-Ben