v0.13.0

What's Changed

• Naive rollback support (down migrations) — add an optional paired {VERSION}_{name}.down.sql file next to a migration and reverse applied migrations with the new down subcommand (--steps N / --to VERSION / --dry-run). On rollback the down statements run (newest first) and the row is removed from schema_versions, so status reports the migration as pending again.

  It is deliberately naive: ClickHouse has no transactional DDL, so there is no automatic rollback. Reversible changes (CREATE TABLE ↔ DROP TABLE, ADD COLUMN ↔ DROP COLUMN) roll back cleanly; destructive ones (data-losing drops, ALTER … DELETE/UPDATE mutations) stay your responsibility. down by @zifter in #69, closes #36 and #67.

Full Changelog: v0.12.0...v0.13.0