# File app/mailsender/mail_sender.rb, line 63
        def add_attachment(file_path)
                filename = File.basename(file_path)
                attachment_data = File.open(file_path, "rb").read
                encoded_attachment = [attachment_data].pack('m')
                @content << "--#{BOUNDARY}\n"
                @content << "Content-Type: application/octet-stream; name=\"#{filename}\"\n"
                @content << "Content-Disposition: attachment; filename=\"#{filename}\"\n"
                @content << "Content-Transfer-Encoding: base64\n"
                @content << "\n"
                @content << "#{encoded_attachment}\n"
        end