Added routing to join a cluster by the UUID.

app/controllers/counter_controller.rb

@@ -8,6 +8,7 @@ class CounterController < ApplicationController
   private
 
   def associate!
+    session[:cluster_uuid] = params[:uuid] if params[:uuid]
     redirect_to cluster_path unless valid_cluster?
   end
 end

config/routes.rb

@@ -3,6 +3,8 @@
 Rails.application.routes.draw do
   root 'counter#show'
 
-  get  '/cluster', to: 'cluster#new'
+  get  '/cluster', to: 'cluster#show'
   post '/cluster', to: 'cluster#create'
+
+  get '/cluster/:uuid', to: 'counter#show'
 end