Boxfuse 
Grails 3.x is based on Spring Boot comes with out-of-the-box integration for Flyway.
All you need to do is add flyway-core to your build.gradle:
compile "org.flywaydb:flyway-core:4.2.0"
Spring Boot will then automatically autowire Flyway with its DataSource and invoke it on startup.
You can then configure a good number of Flyway properties directly from your application.properties or application.yml file.
Boxfuse
Grails 2.x doesn't come with out-of-the-box support for Flyway, however Denis Kuzmin and Bulat Nigmatullin have created a Grails 2 Plugin to remedy this.