Add simple admin overview of PuSH subscriptions

spec/controllers/admin/pubsubhubbub_controller_spec.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+require 'rails_helper'
+
+RSpec.describe Admin::PubsubhubbubController, type: :controller do
+  describe 'GET #index' do
+    before do
+      sign_in :user, Fabricate(:user, admin: true)
+    end
+
+    it 'returns http success' do
+      get :index
+      expect(response).to have_http_status(:success)
+    end
+  end
+end