Both http://flywaydb.org and http://jooq.org would greatly profit if Gradle was pushed to Maven Central. No matter whether people use Maven for their builds or not, Maven Central is the repository for Open Source software. Gradle not being available from Maven Central makes things so complicated for many people. If it were in Maven Central, it would be even better adopted!
To get you started, here’s a nice link explaining how to get jars into Maven Central through Sonatype’s OSS services: https://docs.sonatype.org/display/Repository/Sonatype+OSS+Maven+Repository+Usage+Guide