One of the under-documented elements of Rails is the options available during configuration. Technically, these elements are documented (there are explanations for each in the source code) however they do not appear in the online documentation at api.rubyonrails.org. To assist myself and others I have created a Rails 2.x Configuration Cheat Sheet. I’ve placed it up on github, so feel free to use it within the constraints of the license (Attribution-Noncommercial-Share Alike 3.0 United States).