Improved json auto save & budget mobile UI

lib/repositories/metadata/models/settings.dart

@@ -0,0 +1,19 @@
+import 'package:flutter/material.dart';
+
+class Settings {
+  final ThemeMode themeMode;
+
+  const Settings({
+    this.themeMode = ThemeMode.system,
+  });
+
+  factory Settings.fromJson(Map<String, dynamic> json) {
+    return Settings(
+      themeMode: ThemeMode.values.byName(json['themeMode']),
+    );
+  }
+
+  Map<String, String> toJson() => {
+    'themeMode': themeMode.name,
+  };
+}