def expand_url(input, url=nil)
      url ||= root

      url = if input.start_with?("http", url)
        input
      else
        File.join(url, input)
      end

      smart_slash(url)
    end
def expand_url(input, url=nil)
      url ||= root

      url = if input.start_with?("http", url)
        input
      else
        File.join(url, input)
      end

      smart_slash(url)
    end
Prepends input with a url fragment

 input - An absolute url, e.g. /images/awesome.gif
 url   - The fragment to prepend the input, e.g. /blog

 Returns the modified url, e.g /blog