When I ran the demo, I noticed that the connections to the Redis server still persisted even after the websocket closed. I updated the Gemfile to pull the "em-hiredis" directly from mloughran's Github instead of RubyGems (the RubyGems's version didn't have a Client#close_connection method). Additionally, I updated your method call from "close_connection_after_writing" to "close_connection" which previously wouldn't close the connection.
Just wanted to say it was a great demo, and I hope these fixes will help the next developer who stumbles upon it :).
Updated Gemfile to pull latest em-hiredis from git
Updated close_connection_after_writing to close_connection