changed the way we get the total of products in sale

app/views/sales/index.html.erb

@@ -124,7 +124,7 @@
                           Apartado
                           <% end %>
                         </td>
-                        <td><%= sale.products.count %></td>
+                        <td><%= sale.sales_details.sum(:quantity).round %></td>
                         <td>
                           <% case sale.status %>
                           <% when "paid"%>