Add RootController

This controller is now the target for `root_url`. It sub-classes
DashboardController so we can render the old default without a redirect
if the user hasn't customized their dashboard location.

cherry-picked

app/controllers/root_controller.rb

+# RootController
+#
+# This controller exists solely to handle requests to `root_url`. When a user is
+# logged in and has customized their `dashboard` setting, they will be
+# redirected to their preferred location.
+#
+# For users who haven't customized the setting, we simply delegate to
+# `DashboardController#show`, which is the default.
+class RootController < DashboardController
+  def show
+    case current_user.try(:dashboard)
+    when 'stars'
+      redirect_to starred_dashboard_projects_path
+    else
+      super
+    end
+  end
+end

app/views/layouts/nav/_dashboard.html.haml

 %ul.nav.nav-sidebar
   = nav_link(path: 'dashboard#show', html_options: {class: 'home'}) do
-    = link_to root_path, title: 'Home', class: 'shortcuts-activity', data: {placement: 'right'} do
+    = link_to dashboard_path, title: 'Home', class: 'shortcuts-activity', data: {placement: 'right'} do
       = icon('dashboard fw')
       %span
         Your Projects

config/routes.rb

@@ -293,7 +293,7 @@ Gitlab::Application.routes.draw do
     get '/users/auth/:provider/omniauth_error' => 'omniauth_callbacks#omniauth_error', as: :omniauth_error
   end
 
-  root to: "dashboard#show"
+  root to: "root#show"
 
   #
   # Project Area

spec/controllers/root_controller_spec.rb

+require 'spec_helper'
+
+describe RootController do
+  describe 'GET show' do
+    context 'with a user' do
+      let(:user) { create(:user) }
+
+      before do
+        sign_in(user)
+        allow(subject).to receive(:current_user).and_return(user)
+      end
+
+      context 'who has customized their dashboard setting' do
+        before do
+          user.update_attribute(:dashboard, 'stars')
+        end
+
+        it 'redirects to their specified dashboard' do
+          get :show
+          expect(response).to redirect_to starred_dashboard_projects_path
+        end
+      end
+
+      context 'who uses the default dashboard setting' do
+        it 'renders the default dashboard' do
+          get :show
+          expect(response).to render_template 'dashboard/show'
+        end
+      end
+    end
+  end
+end

spec/routing/routing_spec.rb

@@ -204,11 +204,9 @@ end
 #                dashboard GET    /dashboard(.:format)                dashboard#show
 #         dashboard_issues GET    /dashboard/issues(.:format)         dashboard#issues
 # dashboard_merge_requests GET    /dashboard/merge_requests(.:format) dashboard#merge_requests
-#                     root        /                                   dashboard#show
 describe DashboardController, "routing" do
   it "to #index" do
     expect(get("/dashboard")).to route_to('dashboard#show')
-    expect(get("/")).to route_to('dashboard#show')
   end
 
   it "to #issues" do
@@ -220,6 +218,14 @@ describe DashboardController, "routing" do
   end
 end
 
+#                     root        /                                   root#show
+describe RootController, 'routing' do
+  it 'to #show' do
+    expect(get('/')).to route_to('root#show')
+  end
+end
+
+
 #        new_user_session GET    /users/sign_in(.:format)               devise/sessions#new
 #            user_session POST   /users/sign_in(.:format)               devise/sessions#create
 #    destroy_user_session DELETE /users/sign_out(.:format)              devise/sessions#destroy