ALTER TABLE `events`
  ADD COLUMN `online_platform` VARCHAR(32) NOT NULL DEFAULT 'other' AFTER `online_url`,
  ADD COLUMN `online_platform_other` VARCHAR(120) NULL AFTER `online_platform`,
  ADD COLUMN `online_url_private` TINYINT(1) NOT NULL DEFAULT 1 AFTER `online_platform_other`,
  ADD COLUMN `registration_mode` VARCHAR(32) NOT NULL DEFAULT 'free' AFTER `online_url_private`,
  ADD COLUMN `external_platform` VARCHAR(32) NULL AFTER `registration_mode`,
  ADD COLUMN `external_url` VARCHAR(2048) NULL AFTER `external_platform`;
