added an about page

lib/main.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 
+import 'pages/about_page.dart';
 import 'pages/flood_station_page.dart';
 import 'pages/main_navigation_scaffold.dart';
 import 'services/flood_station_provider.dart';
@@ -31,6 +32,7 @@ class MyApp extends StatelessWidget {
       routes: {
         MainNavigationScaffold.routeName: (context) => MainNavigationScaffold(),
         FloodStationPage.routeName: (context) => FloodStationPage(),
+        AboutPage.routeName: (context) => AboutPage(),
       },
     );
   }

lib/pages/about_page.dart

@@ -0,0 +1,29 @@
+import 'package:flutter/material.dart';
+
+class AboutPage extends StatelessWidget {
+  const AboutPage({super.key});
+
+  static const String aboutText = '''
+This App was build for demonstration purposes.
+It requests data from the Environment Agency Real Time flood-monitoring API and displays a list and map of all flood measurement stations,
+as well as a graph showing the last 24 hours of measurements.
+The source code can be found at https://git.skup.in/.
+                          ''';
+
+  static const String routeName = '/about';
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('About'),
+      ),
+      body: Center(
+        child: Text(
+          aboutText,
+          style: Theme.of(context).textTheme.bodyLarge,
+        ),
+      ),
+    );
+  }
+}

lib/pages/main_navigation_scaffold.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 
+import 'about_page.dart';
 import 'landing_page.dart';
 import 'map_page.dart';
 
@@ -23,6 +24,16 @@ class _MainNavigationScaffoldState extends State<MainNavigationScaffold> {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
+      appBar: AppBar(
+        title: Text('Floodwatch'),
+        actions: [
+          IconButton(
+            onPressed: () =>
+                Navigator.of(context).pushNamed(AboutPage.routeName),
+            icon: Icon(Icons.info_outline),
+          )
+        ],
+      ),
       bottomNavigationBar: NavigationBar(
         selectedIndex: _selectedPageIndex,
         onDestinationSelected: (value) => setState(() {