Download the web server gem webrick by running

$ bundle install

Then start the web server by running

$ bundle exec ruby web_server.rb

You should get a similar output to this:

[2025-03-24 14:52:56] INFO  WEBrick 1.9.1
[2025-03-24 14:52:56] INFO  ruby 3.4.1 (2024-12-25) [arm64-darwin24]
[2025-03-24 14:52:56] INFO  WEBrick::HTTPServer#start: pid=54103 port=8000

Now you can open your browser and go to this URL:

http://localhost:8000/

You should see some gray text saying: "Hello Web App!"