Add initial email route

app/controllers/admin/emails_controller.rb

+class Admin::EmailsController < Admin::ApplicationController
+  def index
+    render text: 'hello world', layout: nil
+  end
+end

config/routes.rb

@@ -86,6 +86,7 @@ Gitlab::Application.routes.draw do
     resources :broadcast_messages, only: [:index, :create, :destroy]
     resource :logs, only: [:show]
     resource :background_jobs, controller: 'background_jobs', only: [:show]
+    resources :emails, only: [:index]
 
     resources :projects, constraints: { id: /[a-zA-Z.\/0-9_\-]+/ }, only: [:index, :show] do
       member do

spec/routing/admin_routing_spec.rb

@@ -119,3 +119,8 @@ describe Admin::DashboardController, "routing" do
   end
 end
 
+describe Admin::EmailsController, "routing" do
+  it "to #index" do
+    get("/admin/emails").should route_to('admin/emails#index')
+  end
+end