minibot.gs

var token = 'TOKEN DE TELEGRAM';
var telegramUrl = 'https://api.telegram.org/bot' + token;
var spreadsheetId = 'ID DEL SPREADSHEET';

function doGet(e) {
  return HtmlService.createHtmlOutput('Hola');
}

function sendText(id, answer) {
  var url = telegramUrl + '/sendMessage?chat_id=' + id + '&text=' + answer;
  UrlFetchApp.fetch(url);
}

function doPost(e) {
  var contents = JSON.parse(e.postData.contents);

  var text = contents.message.text;
  var id = contents.message.chat.id;
  var name = contents.message.chat.first_name;

  var spreadsheet = SpreadsheetApp.openById(spreadsheetId).getSheetByName('Mensajes');
  spreadsheet.appendRow([new Date(), id, name, text]);

  GmailApp.sendEmail('AQUÍ VA EL EMAIL QUE RECIBE EL CORREO', 'Bot de Telegram', JSON.stringify(contents));

  switch (text) {
    case '/start':
      var answer = 'Me has iniciado';
      sendText(id, answer);
      break;
    case '/info':
      var answer = 'Esto es un bot de prueba';
      sendText(id, answer);
      break;
    default:
      var answer = 'No te he entendido';
      sendText(id, answer);
      break;
  }
}