Windows10(64bit) で Ruby 2.2.3 + Rails 4.2.5 ref: http://qiita.com/sasanquaneuf/items/068ab4e5940a790327ba

app\controllers\sampledesu_controller.rb

class SampledesuController < ApplicationController
  def index
    render :text => "Hello, world!にほんご"
  end
end

config\routes.rb

Rails.application.routes.draw do
  root 'sampledesu#index'
end

file0.txt

> cd c:\devkit
> ruby dk.rb init
> ruby dk.rb install

file1.txt

[INFO] Updating convenience notice gem override for 'C:/Ruby22-x64'
[INFO] Installing 'C:/Ruby22-x64/lib/ruby/site_ruby/devkit.rb'

file10.txt

c:\temp\sample>rails server
=> Booting WEBrick
=> Rails 4.2.5 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server

file2.txt

> cp C:\temp\bin\*.dll C:\temp\lib

file3.txt

> gem install nokogiri --platform=ruby -- --use-system-libraries --with-iconv-include=C:/temp/include --with-iconv-lib=C:/temp/lib --with-xml2-include=C:/temp/include/libxml2 --with-xml2-lib=C:/temp/lib --with-xslt-include=C:/temp/include --with-xslt-lib=C:/temp/lib
> gem install nokogiri

file4.txt

> cp C:\temp\lib\*.dll C:\Ruby22-x64\bin

file5.txt

> gem install rails

file6.txt

> cd c:\temp\sample
> rails new ./
> rails generate controller sampledesu

file7.txt

c:\temp\sample>rails generate controller sampledesu
      create  app/controllers/sampledesu_controller.rb
      invoke  erb
      create    app/views/sampledesu
      invoke  test_unit
      create    test/controllers/sampledesu_controller_test.rb
      invoke  helper
      create    app/helpers/sampledesu_helper.rb
      invoke    test_unit
      invoke  assets
      invoke    coffee
      create      app/assets/javascripts/sampledesu.coffee
      invoke    scss
      create      app/assets/stylesheets/sampledesu.scss