code: def reviewboard(client, channel, nick, message, matches):
      
      url_fmt = getattr(settings, 'REVIEWBOARD_URL', 'http://localhost/{review}')
      reviews = [url_fmt.format(review=cr) for cr in matches]
      return '{0} might be talking about codereview: {1}'.format(nick, ', '.join(reviews))
docs: Automatically responds to reviewboard urls if a user mentions a pattern
      like cr####. Requires REVIEWBOARD_URL to exist in settings with formattable
      substring '{review}'