improve shutdown routine

app/lib/features/user/data/providers.dart

@@ -25,7 +25,7 @@ import 'package:path/path.dart' as p;
 import 'package:riverpod/experimental/persist.dart';
 import 'package:riverpod_annotation/riverpod_annotation.dart';
 import 'package:sqlite3_flutter_libs/sqlite3_flutter_libs.dart';
-
+import 'package:weblibre/core/database_registry.dart';
 import 'package:weblibre/core/filesystem.dart';
 import 'package:weblibre/data/database/functions/lexo_rank_functions.dart';
 import 'package:weblibre/features/user/data/database/database.dart';
@@ -53,6 +53,8 @@ UserDatabase userDatabase(Ref ref) {
     }),
   );
 
+  DatabaseRegistry.instance.register('user', db);
+
   ref.onDispose(() async {
     await db.close();
   });