Add sub links to overview

app/views/admin/dashboard/_head.html.haml

+%ul.nav-links.sub-nav
+  %div{ class: (container_class) }
+    = nav_link(controller: :dashboard, html_options: {class: 'home'}) do
+      = link_to admin_root_path, title: 'Overview' do
+        %span
+          Overview
+    = nav_link(controller: [:admin, :projects]) do
+      = link_to admin_namespaces_projects_path, title: 'Projects' do
+        %span
+          Projects
+    = nav_link(controller: :users) do
+      = link_to admin_users_path, title: 'Users' do
+        %span
+          Users
+    = nav_link(controller: :groups) do
+      = link_to admin_groups_path, title: 'Groups' do
+        %span
+          Groups

app/views/admin/dashboard/index.html.haml

-.admin-dashboard.prepend-top-default
+- @no_container = true
+= render "admin/dashboard/head"
+
+%div{ class: (container_class) }
+  .admin-dashboard.prepend-top-default
     .row
       .col-md-4
         %h4 Statistics

app/views/admin/groups/index.html.haml

+- @no_container = true
 - page_title "Groups"
-%h3.page-title
+= render "admin/dashboard/head"
+
+%div{ class: (container_class) }
+  %h3.page-title
     Groups (#{number_with_delimiter(@groups.total_count)})
 
-%p.light
+  %p.light
     Group allows you to keep projects organized.
     Use groups for uniting related projects.
 
-.top-area
+  .top-area
     .nav-search
       = form_tag admin_groups_path, method: :get, class: 'form-inline' do
         = hidden_field_tag :sort, @sort
@@ -34,8 +38,8 @@
               = sort_title_oldest_updated
       = link_to 'New Group', new_admin_group_path, class: "btn btn-new"
 
-%ul.content-list
+  %ul.content-list
     - @groups.each do |group|
       = render 'group', group: group
 
-= paginate @groups, theme: "gitlab"
+  = paginate @groups, theme: "gitlab"

app/views/admin/projects/index.html.haml

+- @no_container = true
 - page_title "Projects"
 = render 'shared/show_aside'
+= render "admin/dashboard/head"
 
-.row.prepend-top-default
+%div{ class: (container_class) }
+  .row.prepend-top-default
     %aside.col-md-3
       .panel.admin-filter
         = form_tag admin_namespaces_projects_path, method: :get, class: '' do

app/views/admin/users/index.html.haml

+- @no_container = true
 - page_title "Users"
 = render 'shared/show_aside'
+= render "admin/dashboard/head"
 
-.admin-filter
+%div{ class: (container_class) }
+  .admin-filter
     %ul.nav-links
       %li{class: "#{'active' unless params[:filter]}"}
         = link_to admin_users_path do
@@ -68,7 +71,7 @@
           %i.fa.fa-search
 
 
-.panel.panel-default
+  .panel.panel-default
     %ul.well-list
       - @users.each do |user|
         %li
@@ -104,4 +107,4 @@
                   = link_to 'Unlock', unlock_admin_user_path(user), method: :put, class: 'btn-grouped btn btn-xs btn-success', data: { confirm: 'Are you sure?' }
                 - if user.can_be_removed?
                   = link_to 'Destroy', [:admin, user], data: { confirm: "USER #{user.name} WILL BE REMOVED! All issues, merge requests and groups linked to this user will also be removed! Maybe block the user instead? Are you sure?" }, method: :delete, class: 'btn-grouped btn btn-xs btn-remove'
-= paginate @users, theme: "gitlab"
+  = paginate @users, theme: "gitlab"

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

 %ul.nav-links.scrolling-tabs
   .fade-left
-  = nav_link(controller: :dashboard, html_options: {class: 'home'}) do
-    = link_to admin_root_path, title: 'Overview' do
+  = nav_link(controller: %w(dashboard admin projects users groups), html_options: {class: 'home'}) do
+    = link_to admin_root_path, title: 'Overview', class: 'shortcuts-tree' do
       %span
         Overview
-  = nav_link(controller: [:admin, :projects]) do
-    = link_to admin_namespaces_projects_path, title: 'Projects' do
-      %span
-        Projects
-  = nav_link(controller: :users) do
-    = link_to admin_users_path, title: 'Users' do
-      %span
-        Users
-  = nav_link(controller: :groups) do
-    = link_to admin_groups_path, title: 'Groups' do
-      %span
-        Groups
   = nav_link(controller: :deploy_keys) do
     = link_to admin_deploy_keys_path, title: 'Deploy Keys' do
       %span