code: function renderButton(data)
  {
    var message, limit = 3;
  
    if (data.buttons.length > limit)
    {
      this.logger.warn({message: 'Truncated provided list of buttons to first ' + limit + ' elements (maximum for the Button Template)', data: data});
      data.buttons = data.buttons.slice(0, limit);
    }
  
    message = {
      attachment: {
        type: 'template',
        payload: {
          template_type: 'button',
          text         : data.text,
          buttons      : data.buttons
        }
      }
    };
  
    this.logger.debug({message: 'Generated message payload with Button Template', payload: message});
  
    return message;
  }
docs: Renders payload from provided data with button template
  https://developers.facebook.com/docs/messenger-platform/send-api-reference/button-template
  
  @this    Fbbot#
  @param   {object} data - text + buttons object
  @returns {object} - button template message payload