;;in example.migration
(defn clean-db [& [force?]]
  (if-not force?
    (throw (Throwable.
      "This is a destructive action! Pass in `force' to make this go through"))
    (let [datasource (get-db-datasource)
          flyway (doto (Flyway.)
                   (.setDataSource datasource)
                   (.setSqlMigrationPrefix ""))]
      (.clean flyway))))

;; and a nice alias in the project.clj
:aliases {"migrate" ["run" "-m" "example.migration/migrate"]
          "clean" ["run" "-m" "example.migration/clean-db"]})