The source file should go into the lib/ directory. That directory is
automatically added to $LOAD_PATH by the Rails initialization process.
You can "require" the file in several ways:
1. Use a require statement at the point of need.
2. Add a require statement to config/environment.rb
3. Take advantage of rails' magic auto-loading gizmo that will
automatically load some_class.rb if you reference SomeClass and it's
not already defined.
See also:
http://toolmantim.com/article/2006/12/27/environments_and_the_rails_initialisation_process
