DHH made a Action Cable demo where he builds a chat-application: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=n0WUjGkDFS0" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=n0WUjGkDFS0</a>