helper.rb

  def nav_link_to(title, url, options={})
    content_tag :li, li_options(options) do
      link_to title, url
    end
  end

  def li_options(options)
    link_matches? ? {class: "active"} : {}
  end

  def link_matches?(options)
    url_matches?(options[:url]) || path_matches?(options[:path]) || controller_matches?(options[:controller], options[:action])
  end

  def url_matches?(url)
    url == "#{request.protocol}#{request.host_with_port}#{request.fullpath}"
  end

  def path_matches?(path)
    path == request.fullpath
  end

  def controller_matches?(kontroller, action)
    kontroller == params[:controller] && (action == nil || action == params[:action])
  end