windows下安装或升级rails

windows下安装或升级时gem经常会碰到1PleaseupdateyourPATHtoincludebuildtoolsordownloadtheDevKit2from'http://rubyinstaller.org/downloads'andfollowtheinstructions3at'http://github.com/oneclick/rubyinstaller/wiki/Development-Kit'这是因为没有安装DevKit的缘故。