How to initialize a Gem in Rails 3? How to register Template Handlers?

My gem works fine with Rails 2.3 (using Bundler) but I cannot get it loaded in Rails 3.

my_app/Gemfile:

 gem 'mygem', '>= 0.1.0', :path => '../mygem/'

I know that it is found because I managed to get it "working" once.

I've read between the lines of many blog posts and rails tickets that rails/init.rb is deprecated and a toplevel init.rb should be used that requires the main lib file. However, none of them gets executed unless I require 'my_gem'explicitly in my Rails app. This is how it looks like at the moment:

mygem/init.rb`:

require File.join(File.dirname(__FILE__), 'lib', 'my_gem')
raise StandardError, "derailed!"

mygem/lib/my_gem:

require 'my_gem/template_handler'
raise Standa开发者_开发知识库rdError, "derailed!"

module MyGem
  class Railtie < Rails::Railtie
    raise StandardError, "derailed!"
    initializer "template handler registration" do
      raise StandardError, "derailed!"
      ActionView::Template.register_template_handler :act, TemplateHandler
    end
  end
end

ActionView::Template.register_template_handler :act, TemplateHandler

I cluttered everything with raise statements... the fact that none of them is raised makes me think that all my attempts to register my template handler have been in vain... ;)

I am running out of ideas to get my gem loaded. my_gem/lib is in the $LOAD_PATH, everything seems to be fine.