rails本地安装
安装的gem包假设放在C：/ruby/下，打开命令行窗口，进入Ｃ:/ruby/目录。 接着运行如下命令，即可完成安装：
gem install rake-0.8.1.gem
gem install activesupport-2.1.0.gem
gem install activerecord-2.1.0.gem
gem install actionpack-2.1.0.gem
gem install actionmailer-2.1.0.gem
gem install activeresource-2.1.0.gem
gem install rails-2.1.0.gem
