persistence/sql/migrations/20190400000008000000_oauth2.down.sql
ALTER TABLE hydra_oauth2_access DROP COLUMN challenge_id;
ALTER TABLE hydra_oauth2_refresh DROP COLUMN challenge_id;
ALTER TABLE hydra_oauth2_code DROP COLUMN challenge_id;
ALTER TABLE hydra_oauth2_oidc DROP COLUMN challenge_id;
ALTER TABLE hydra_oauth2_pkce DROP COLUMN challenge_id;