Add date_updated field in adlist table set when a list changes.

Signed-off-by: DL6ER <dl6er@dl6er.de>

advanced/Scripts/database_migration/gravity/12_to_13.sql

@@ -0,0 +1,11 @@
+.timeout 30000
+
+PRAGMA FOREIGN_KEYS=OFF;
+
+BEGIN TRANSACTION;
+
+ALTER TABLE adlist ADD COLUMN date_updated INTEGER;
+
+UPDATE info SET value = 13 WHERE property = 'version';
+
+COMMIT;