…me gem YSRedCloth for our use
… was in previous (working) versions of RedCloth.
I just installed a fresh copy and `irb; require 'rubygems'; require 'redcloth'` was failing with a No Such File error. Printing out $: revealed a wrong path. Documentation indicated that require_path expects a string. require_paths is an array, and by default it already includes 'lib', so we simply concatenate to it (http://docs.rubygems.org/read/chapter/20#require_paths)