module Roda::RodaPlugins::Base::ClassMethods

def plugin(plugin, *args, &block)

Roda.plugin :csrf
Roda.plugin PluginModule

which will be required and then used. Returns nil.
which is used directly, or a symbol represented a registered plugin
Load a new plugin into the current class. A plugin can be a module 
def plugin(plugin, *args, &block)
  raise RodaError, "Cannot add a plugin to a frozen Roda class" if frozen?
  plugin = RodaPlugins.load_plugin(plugin) if plugin.is_a?(Symbol)
  plugin.load_dependencies(self, *args, &block) if plugin.respond_to?(:load_dependencies)
  include(plugin::InstanceMethods) if defined?(plugin::InstanceMethods)
  extend(plugin::ClassMethods) if defined?(plugin::ClassMethods)
  self::RodaRequest.send(:include, plugin::RequestMethods) if defined?(plugin::RequestMethods)
  self::RodaRequest.extend(plugin::RequestClassMethods) if defined?(plugin::RequestClassMethods)
  self::RodaResponse.send(:include, plugin::ResponseMethods) if defined?(plugin::ResponseMethods)
  self::RodaResponse.extend(plugin::ResponseClassMethods) if defined?(plugin::ResponseClassMethods)
  plugin.configure(self, *args, &block) if plugin.respond_to?(:configure)
  nil
end