def validate!

      if title.blank?
        raise RuntimeError, "HelpLinks must provide a string title"
      end

      file_configured = (slug.present? && markdown_file.present?)
      link_configured = link_to.present?

      unless file_configured || link_configured
        raise RuntimeError, "Incomplete HelpLink config. You must provide link_to, or both slug and markdown_file."
      end

      if file_configured && link_configured
        raise RuntimeError, "Ambiguous HelpLink config. You must provide link_to, or both slug and markdown_file, but not all three."
      end

    end
def validate!

      if title.blank?
        raise RuntimeError, "HelpLinks must provide a string title"
      end

      file_configured = (slug.present? && markdown_file.present?)
      link_configured = link_to.present?

      unless file_configured || link_configured
        raise RuntimeError, "Incomplete HelpLink config. You must provide link_to, or both slug and markdown_file."
      end

      if file_configured && link_configured
        raise RuntimeError, "Ambiguous HelpLink config. You must provide link_to, or both slug and markdown_file, but not all three."
      end

    end
Raises RuntimeError if this HelpLink is incorrectly configured.