Looks like the author is using a server side route and controller just to render the initial view - and then beyond that he has two channels: one for players to

Looks like the author is using a server side route and controller just to render the initial view - and then beyond that he has two channels: one for players to join a game and one for managing game mechanics. I'm just learning Elixir and Phoenix myself. Looking at the source of this it is apparent even to me a newbie that a two player game where game state is managed as a supervised process - and the server manages many games is a nice example of the power of Elixir/Erlang to facilitate concurrent development.