run ruby in xCode

(1) use organizer:
Window --> organizer

(2) add folder with ruby file to organizer

(3) edit Actions:
Run--> edit Actions
in left panel: add item name
in right panel: Directory: Top level Organizer level
command path: /usr/bin/ruby
arguments: ruby file name, ex: test.rb

(4) Then we can run ruby program from run button