App Setting, Where To Put: environment.rb, initializer.rb, lib..?

I have a path that my model (Audio) uses to r/w files. This path
differs between production, test, and dev.

Audio includes a module that overrides some ActiveRecord methods.
This module is contained in config/initializers.

I'd like to set the Audio directory based on my environment, but using
the given environment files fail because the module included by Audio
hasn't been loaded. Of course I could just require it, but this made
me think that maybe the initilaizers directory isn't the right place
to put my AR overrides, and the environment file isn't the right place
to put my non-Rails related environment settings. Is this the case?

It seems as though I should set the directory in it's own initializer
based on RAILS_ENV... but Rails is already doing this for me with the
given environment files

I think the environment files are where you should set the different
directories. I do think that the AR overrides should go into /lib..

If you want to change when something loads in the environments files
config.after_initialize do

Here is an old but good article that talks about these issues and