Duh. rvm doesn't want sudo.

cruise_config.rb

 require 'fileutils'
 
 Project.configure do |project|
-  project.build_command = 'cd .. && cd work && sudo gem update --system && ruby lib/cruise/build.rb'
+  project.build_command = 'cd .. && cd work && gem update --system && ruby lib/cruise/build.rb'
 end