Archive old migrations (#426)

* Archive old migrations

* Fix invalid placement of migrations

migrations/archive/000.493.sql

@@ -0,0 +1,4 @@
+-- Ensure display_name values are null, and not empty strings.
+-- So that coalesce(display_name, name) logic works as intended.
+-- There are five of these values, for hidden category, the source is a mass import excel.
+UPDATE category_texts SET display_name = null where category_id = 1689 and display_name is not null;