gem_plugin is clever

gem_plugin is a rubygem with a difference. Zed wrote it to allow people to easily publish plugins for his mongrel httpserver. If you create a gem with mongrel and gem_plugin as dependencies, gem_plugin will load your gem and run its init.rb after mongrel has loaded.

This makes it really easy for end users wanting to use your plugin. They just run

sudo gem install your_plugin__name

and the next time they run mongrel your plugin will be loaded. Very nice. The app doesn't need to be told to load the plugin.