Ruby provides many useful plug-ins, which you can use in your Rails applications. Here are few scripts, which help you to deal with plug-ins.
|script/plugin discover||Discovers plugin repositories.|
|script/plugin list||Lists all available plugins.|
|script/plugin install where||Installs the "where" plugin.|
|script/plugin install -x where||Installs the "where" plugin as SVN external.|
|script/plugin update||Updates installed plugins.|
|script/plugin source||Adds a source repository.|
|script/plugin unsource||Removes a source repository.|
|script/plugin sources||Lists source repositories.|
Check following link for more information on Rails Plug-in.