Ruby on rails devkit windows

У меня проблема с установкой devkit ruby ​​на рельсы. Вот ошибка, которую я получил

C:\DevKit>ruby dk.rb review
Based upon the settings in the 'config.yml' file generated
from running 'ruby dk.rb init' and any of your customizations,
DevKit functionality will be injected into the following Rubies
when you run 'ruby dk.rb install'.

C:/Ruby192
C:/Ruby192/include/ruby-1.9.1

C:\DevKit>ruby dk.rb install
[INFO] Updating convenience notice gem override for 'C:/Ruby192'
[INFO] Installing 'C:/Ruby192/lib/ruby/site_ruby/devkit.rb'
[ERROR] Unable to find RubyGems in site_ruby or core Ruby. Please install RubyGems and rerun 'ruby dk.rb install'.

Пожалуйста, помогите мне

Спасибо