Add ping/pong health check

spec/routing/ping_routing_spec.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe PingController, type: :routing do
+  context 'with routes to #show' do
+    it { expect(get: '/ping').to route_to('ping#index', format: :json) }
+  end
+end