Use number_with_delimiter for Todos pending/done tab counts

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

@@ -9,14 +9,14 @@
         %span
           To do
         %span.badge
-          = todos_pending_count
+          = number_with_delimiter(todos_pending_count)
     - todo_done_active = ('active' if params[:state] == 'done')
     %li{class: "todos-done #{todo_done_active}"}
       = link_to todos_filter_path(state: 'done') do
         %span
           Done
         %span.badge
-          = todos_done_count
+          = number_with_delimiter(todos_done_count)
 
   .nav-controls
     - if @todos.any?(&:pending?)