text: -- +migrate Up
  ALTER TABLE `users_answers`
    COMMENT 'All the submissions made by users on tasks, as well as saved answers and the current answer',
    MODIFY COLUMN `sState` mediumtext COMMENT 'Saved state (sent by the task platform)',
    MODIFY COLUMN `sAnswer` mediumtext COMMENT 'Saved answer (sent by the task platform)',
    MODIFY COLUMN `sLangProg` varchar(50) DEFAULT NULL COMMENT 'Programming language of this submission',
    MODIFY COLUMN `sSubmissionDate` datetime NOT NULL COMMENT 'Submission time',
    MODIFY COLUMN `iScore` float DEFAULT NULL COMMENT 'Score obtained',
    MODIFY COLUMN `bValidated` tinyint(1) DEFAULT NULL COMMENT 'Whether it is considered "validated" (above validation threshold for this item)',
    MODIFY COLUMN `sGradingDate` datetime DEFAULT NULL COMMENT 'When was it last graded',
    MODIFY COLUMN `idUserGrader` int(11) DEFAULT NULL COMMENT 'Who did the last grading';
  
  -- +migrate Down
  ALTER TABLE `users_answers`
    COMMENT '',
    MODIFY COLUMN `sState` mediumtext,
    MODIFY COLUMN `sAnswer` mediumtext,
    MODIFY COLUMN `sLangProg` varchar(50) DEFAULT NULL,
    MODIFY COLUMN `sSubmissionDate` datetime NOT NULL,
    MODIFY COLUMN `iScore` float DEFAULT NULL,
    MODIFY COLUMN `bValidated` tinyint(1) DEFAULT NULL,
    MODIFY COLUMN `sGradingDate` datetime DEFAULT NULL,
    MODIFY COLUMN `idUserGrader` int(11) DEFAULT NULL;
  