My sample app, 'cabletest1', for using ActionCable and websockets with Redis to keep a connection open.
This app is the chatoom app from a heroku blog post with a couple of minor modifications.
Clone it.
rails db:migrate
rails db:seed
rails server -p3333
You don't have to use port 3333 but if you don't, you'll need to change the ports in config/environments/development.rb
at the bottom of that file.
Also, if you don't have your own Redis server running locally, change config/cable.yml
to the 'async' setting in development.