db, types: add a credentials column for keys a token made

No released version made keys from tokens, so existing rows stay false.

hscontrol/db/schema.sql

@@ -60,6 +60,7 @@ CREATE TABLE credentials(
   created_at datetime,
   expiration datetime,
   revoked datetime,
+  created_by_token numeric DEFAULT false,
 
   CONSTRAINT fk_credentials_user FOREIGN KEY(user_id) REFERENCES users(id) ON DELETE SET NULL,
   CONSTRAINT chk_credentials_hash CHECK(hash IS NOT NULL OR revoked IS NOT NULL),