Actually all you need to do is
require 'active_support/inflector'
and that will extend the String type.
you can then do
"MyString".pluralize
which will return
"MyStrings"
for 2.3.5 try:
require 'rubygems'
require 'active_support/inflector'
should get it, if not try
sudo gem install activesupport
and then the requires.