This is the error message in Windows:
C:\Users\USER\Sites\new_cms>rails s
C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/nokogiri-1.6.6.2-x64-mingw32/lib/nokogir
.rb:29:in `require': cannot load such file -- nokogiri/nokogiri (LoadError)
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/nokogiri-1.6.6.2-x64-mingw3
/lib/nokogiri.rb:29:in `rescue in <top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/nokogiri-1.6.6.2-x64-mingw3
/lib/nokogiri.rb:25:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/loofah-2.0.1/lib/loofah.rb:
:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/loofah-2.0.1/lib/loofah.rb:
:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/rails-html-sanitizer-1.0.2/
ib/rails-html-sanitizer.rb:2:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/rails-html-sanitizer-1.0.2/
ib/rails-html-sanitizer.rb:2:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/sanitize_helper.rb:3:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/sanitize_helper.rb:3:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/text_helper.rb:32:in `<module:TextHelper>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/text_helper.rb:29:in `<module:Helpers>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/text_helper.rb:6:in `<module:ActionView>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/text_helper.rb:4:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/form_tag_helper.rb:18:in `<module:FormTagHelper>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/form_tag_helper.rb:14:in `<module:Helpers>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/form_tag_helper.rb:8:in `<module:ActionView>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/form_tag_helper.rb:6:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/form_helper.rb:4:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers/form_helper.rb:4:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers.rb:50:in `<module:Helpers>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers.rb:4:in `<module:ActionView>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/actionview-4.2.0/lib/action
view/helpers.rb:3:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/legacy_asset_tag_helper.rb:7:in `<module:LegacyAssetTagHelper>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/legacy_asset_tag_helper.rb:6:in `<module:Rails>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/legacy_asset_tag_helper.rb:4:in `<module:Sprockets>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/legacy_asset_tag_helper.rb:3:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/helper.rb:45:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/helper.rb:45:in `<module:Helper>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/helper.rb:7:in `<module:Rails>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/helper.rb:6:in `<module:Sprockets>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/rails/helper.rb:5:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/railtie.rb:6:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sprockets-rails-2.2.4/lib/s
rockets/railtie.rb:6:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sass-rails-5.0.1/lib/sass/r
ils/railtie.rb:2:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sass-rails-5.0.1/lib/sass/r
ils/railtie.rb:2:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sass-rails-5.0.1/lib/sass/r
ils.rb:11:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sass-rails-5.0.1/lib/sass/r
ils.rb:11:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sass-rails-5.0.1/lib/sass-r
ils.rb:1:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/sass-rails-5.0.1/lib/sass-r
ils.rb:1:in `<top (required)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler/r
ntime.rb:76:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler/r
ntime.rb:76:in `block (2 levels) in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler/r
ntime.rb:72:in `each'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler/r
ntime.rb:72:in `block in require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler/r
ntime.rb:61:in `each'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler/r
ntime.rb:61:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.8.5/lib/bundler.r
:134:in `require'
from C:/Users/USER/Sites/new_cms/config/application.rb:7:in `<top (requ
red)>'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/co
mands/commands_tasks.rb:78:in `require'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/co
mands/commands_tasks.rb:78:in `block in server'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/co
mands/commands_tasks.rb:75:in `tap'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/co
mands/commands_tasks.rb:75:in `server'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/co
mands/commands_tasks.rb:39:in `run_command!'
from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.0/lib/rails/co
mands.rb:17:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
C:\Users\USER\Sites\new_cms>
Nokogiri doesn't have binaries for Ruby 2.2.1 available for the mingw32 platform due to some problems with cross compiling Ruby 2.2.1 for the rake-compiler-dev-box.
Since Nokogiri doesn't natively compile on Windows, the only fix is to downgrade to Ruby 2.1.5. Once the next patch level of Ruby 2.2 is released hopefully the problem will be solved.