Scrolling not working in ListView in Flutter Web

main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class SimpleList extends StatefulWidget {
  SimpleList({Key key}) : super(key: key);

  @override
  _SimpleList createState() => _SimpleList();
}

class _SimpleList extends State<SimpleList> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: ListView(
        padding: EdgeInsets.only(
            left: 20, right: 20, bottom: 30),
        physics: AlwaysScrollableScrollPhysics(),
        shrinkWrap: true,
        scrollDirection: Axis.horizontal,
        children: [
          Container(
            color: Colors.red,
            width: 200,
            height: 500
          ),
          Container(
            color: Colors.red,
            width: 200,
            height: 500
          ),
          Container(
            color: Colors.red,
            width: 200,
            height: 500
          ),
          Container(
            color: Colors.red,
            width: 200,
            height: 500
          ),
          Container(
            color: Colors.red,
            width: 200,
            height: 500
          ),
          Container(
            color: Colors.red,
            width: 200,
            height: 500
          ),
        ],
      ),
    );
  }
}

class MyApp extends StatefulWidget {
  MyApp({Key key}) : super(key: key);

  @override
  _MyApp createState() => _MyApp();
}

class _MyApp extends State<MyApp> {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'MyApp',
      home: SimpleList(),
    );
}