Adicione a configuração abaixo em seu arquivo Config.groovy. A migração será executada durante a implantação do WAR.
//===========================DATA MIGRATION============================
//Run changelog.groovy during application deployment on server?
grails.plugin.databasemigration.updateOnStart = true
//File used to run the db migration scripts
grails.plugin.databasemigration.updateOnStartFileNames = ['changelog.groovy']
//Absolute path of changelog.groovy in the app base dir
grails.plugin.databasemigration.changelogLocation = 'migrations'
// the default schema to use when running auto-migrate on start
//grails.plugin.databasemigration. updateOnStartDefaultSchema ='schema' // You may not need this in MYSQL
//=====================================================================
Com base na configuração acima, é assim que sua estrutura de pastas deve ser:
your-grails-project
--migrations/
--changelog.groovy
--migration1.groovy
--migration2.groovy
changelog.groovy
databaseChangeLog = {
include file: 'migration1.groovy'
include file: 'migration2.groovy'
}