Add 'no bills' placeholder.

coin/members/templates/members/invoices.html

@@ -22,6 +22,8 @@
             <td{% if invoice.amount_remaining_to_pay > 0 %} class="unpaid"{% endif %}>{{ invoice.amount_remaining_to_pay }}</td>
             <td>{% if invoice.is_pdf_exists %}<a href="{% url 'billing:invoice_pdf' id=invoice.number %}"><i class="fa fa-file-pdf-o"></i> PDF</a>{% endif %}</td>
         </tr>
+        {% empty %}
+        <tr class="placeholder"><td colspan="6">Aucune facture.</td></tr>
         {% endfor %}
     </tbody>
 </table>