show_simple_captcha in a liquid template

simple_captcha.rb

module Liquid
  module Tags
    module SimpleCaptcha
      class HumanTest < ::Liquid::Tag
        include ::ActionView::Helpers::FormTagHelper
        include ::SimpleCaptcha::ViewHelper

        attr_accessor :request, :session

        def render(context)
          controller   = context.registers[:controller]
          self.request = controller.request
          self.session = controller.session
          context.registers[:controller].send(:render_to_string, :partial => ::SimpleCaptcha.partial_path, :locals =>  { :registers => context.registers, :simple_captcha_options => simple_captcha_options({}) })
        end
      end
    end

    ::Liquid::Template.register_tag('show_simple_captcha_tag', SimpleCaptcha::HumanTest)
  end
end