how about this

michaels_helper.rb

module ApplicationHelper
  def markdown(text, *renderer)
    case renderer[0]
    props = {
      hard_wrap:       true,
      gh_blockcode:    true,
      safe_links_only: true,
      filter_html:     true
    }
    when :authored
      props[:filter_html] = false
    else
      props[:no_images] = true; props[:no_styles] = true
    end
    redcarpet = Redcarpet::Markdown.new(HTMLwithAlbino.new(props),
      space_after_headers: true, fenced_code_blocks: true,
      autolink: true, no_intra_emphasis: true,
      strikethrough: true, superscripts: true
    )
    redcarpet.render(text).html_safe
  end

end

# create a custom renderer that allows highlighting of code blocks
class HTMLwithAlbino < Redcarpet::Render::HTML
  def block_code(code, language)
    Albino.colorize(code, language)
  end
end