Index: app/views/groups/index.html.erb
===================================================================
--- app/views/groups/index.html.erb	(révision 3580)
+++ app/views/groups/index.html.erb	(copie de travail)
@@ -15,7 +15,7 @@
 <% @groups.each do |group| %>
   <tr class="<%= cycle 'odd', 'even' %>">
     <td><%= link_to h(group), edit_group_path(group) %></td>
-    <td align="center"><%= group.users.size %></td>
+    <td align="center"><%= @group_users_count[group.id] || 0 %></td>
     <td class="buttons"><%= delete_link group %></td>
   </tr>
 <% end %>
Index: app/controllers/groups_controller.rb
===================================================================
--- app/controllers/groups_controller.rb	(révision 3601)
+++ app/controllers/groups_controller.rb	(copie de travail)
@@ -26,6 +26,7 @@
 
   def index
     @groups = Group.sorted.all
+    @group_users_count = User.joins(:groups).group('group_id').count
 
     respond_to do |format|
       format.html