Improved json auto save & budget mobile UI

lib/repositories/metadata/models/metadata.dart

@@ -2,16 +2,19 @@ import 'package:tunas/repositories/metadata/models/budget.dart';
 import 'package:tunas/repositories/metadata/models/category.dart';
 import 'package:tunas/repositories/json/models/json.dart';
 import 'package:tunas/repositories/metadata/models/account.dart';
+import 'package:tunas/repositories/metadata/models/settings.dart';
 
 class Metadata implements Json {
   List<Budget> budgets;
   List<Category> categories;
   List<Account> accounts;
+  Settings settings;
 
   Metadata({
     this.budgets = const [],
     this.categories = const [],
     this.accounts = const [],
+    this.settings = const Settings(),
   });
 
   @override

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,
+  };
+}