win32consoleパッケージをインストールすればいいみたい
>gem install win32console Need to update 11 gems from http://gems.rubyforge.org ........... complete Select which gem to install for your platform (i386-mswin32) 1. win32console 1.2.0 (x86-mswin32-60) 2. win32console 1.2.0 (x86-mingw32) 3. win32console 1.1.0 (i386-mswin32) 4. win32console 1.0.8 (i386-mswin32) 5. Skip this gem 6. Cancel installation > 2 Successfully installed win32console-1.2.0-x86-mingw32 Installing ri documentation for win32console-1.2.0-x86-mingw32... Installing RDoc documentation for win32console-1.2.0-x86-mingw32...
