Restore Contribution Analytics to Group navigation

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

@@ -41,6 +41,11 @@
       = icon('users fw')
       %span
         Members
+  = nav_link(controller: [:stats]) do
+    = link_to group_analytics_path(@group), title: 'Contribution Analytics', data: {placement: 'right'} do
+      = icon('bar-chart fw')
+      %span
+        Contribution Analytics
   - if can?(current_user, :admin_group, @group)
     = nav_link(html_options: { class: "separate-item" }) do
       = link_to edit_group_path(@group), title: 'Settings' do