Extending a class from plugin, need always restart serve

Rails reloads everything in /lib too if it was autoloaded.

Be careful about extending your rails app classes from plugins.
Remember that the load cycle goes like this: Rails => Plugins => App.
Plugins can safely monkey patch Rails, since neither are reloaded.
However, modifying your app classes can be troublesome. What if
Plugin A includes itself into Post, yet Post has code that depends on
Plugin A and B? You get an error, that's what.

2 suggestions:

1) It's okay to require users to add code to their app to load
plugins. Requiring a manual "include FooMethods" is fine. It makes
it more explicit that you're using a plugin. Common acts_as_* plugins
will define a single class method on ActiveRecord::Base that does
little more than setting some options and including some modules.

2) I wrote a little "include_into" hack to Module.
http://weblog.techno-weenie.net/2006/11/15/extending-your-rails-classes-from-plugins

I'd advise #1 unless you're pretty familiar with ruby/rails.