Add german translation

lib/app.dart

@@ -1,6 +1,9 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_localizations/flutter_localizations.dart';
 
+import 'backend.dart';
 import 'home_screen.dart';
+import 'localizations.dart';
 
 /// A simple reminder app.
 ///
@@ -9,6 +12,15 @@ class MemorApp extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
+      localizationsDelegates: const [
+        MemorLocalizations.delegate,
+        GlobalMaterialLocalizations.delegate,
+        GlobalWidgetsLocalizations.delegate,
+      ],
+      supportedLocales: const [
+        Locale('en'),
+        Locale('de'),
+      ],
       theme: ThemeData(
         primaryColor: Colors.black,
         accentColor: Colors.amber,
@@ -21,6 +33,7 @@ class MemorApp extends StatelessWidget {
         ),
         fontFamily: 'Libertinus Sans',
       ),
+      builder: (context, child) => MemorBackend(child: child),
       home: HomeScreen(),
     );
   }