[update] added migration scripts for migrating news data to articles, geographic and category tagging, and default sharing templates

backend-rust/migrations/006_update_settings_table.down.sql

@@ -0,0 +1,18 @@
+-- Remove enhanced settings columns and indexes
+DROP INDEX IF EXISTS idx_settings_user_id;
+DROP INDEX IF EXISTS idx_settings_category;
+
+-- Note: SQLite doesn't support DROP COLUMN, so we recreate the table
+CREATE TABLE settings_backup AS
+SELECT key, val
+FROM settings;
+DROP TABLE settings;
+CREATE TABLE settings
+(
+    key TEXT PRIMARY KEY,
+    val TEXT NOT NULL
+);
+INSERT INTO settings
+SELECT key, val
+FROM settings_backup;
+DROP TABLE settings_backup;