Redcarpet (Markdown) template handler for Rails 3.1.

redcarpet.rb

# config/initializers/redcarpet.rb

class ActionView::Template
  class Redcarpet < Handler
    include Handlers::Compilable

    def compile template
      ::Redcarpet.new(template.source).to_html.inspect
    end
  end

  register_template_handler :markdown, Redcarpet
end