MySQL error in Ruby on Rails

Install ruby and ruby on rails on my windows 8.1

I have a problem when launching the server

C:\Sites\testing>rails s
C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2/mysql2.rb:2:in `require': cannot load such file -- mysql2/2.2/mysql2 (LoadError)
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2/mysql2.rb:2:in `<top (required)>'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2.rb:31:in `require'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/mysql2-0.3.18-x64-mingw32/lib/mysql2.rb:31:in `<top (required)>'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler/runtime.rb:76:in `require'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler/runtime.rb:76:in `block (2 levels) in require'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler/runtime.rb:72:in `each'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler/runtime.rb:72:in `block in require'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler/runtime.rb:61:in `each'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler/runtime.rb:61:in `require'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/bundler-1.9.1/lib/bundler.rb:134:in `require'
    from C:/Sites/testing/config/application.rb:7:in `<top (required)>'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:78:in `require'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:78:in `block in server'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `tap'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `server'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from C:/Ruby22-x64/lib/ruby/gems/2.2.0/gems/railties-4.2.1/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

C:\Sites\testing>

Help me please. Thank.