make web version work, add dockerfile

lib/main.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:logging/logging.dart';
+import 'package:pdfrx/pdfrx.dart';
 
 import 'login_page.dart';
 
@@ -12,6 +13,8 @@ void main() {
     }
   });
 
+  pdfrxFlutterInitialize(); // Needed for web
+
   runApp(const MyApp());
 }
 
@@ -22,10 +25,7 @@ class MyApp extends StatelessWidget {
   Widget build(BuildContext context) {
     return MaterialApp(
       title: 'Sheetless',
-      theme: ThemeData(
-        useMaterial3: true,
-        primarySwatch: Colors.blue,
-      ),
+      theme: ThemeData(useMaterial3: true, primarySwatch: Colors.blue),
       home: const LoginPage(),
     );
   }