Add number of references in the same school year for referents

templates/attribution.html

@@ -82,7 +82,7 @@
     <form>{% csrf_token %}
     <div id="referent_choice"><label for="referent_select">Référent:</label>
       <select id="referent_select"><option value="">-------</option>
-        {% for ref in referents %}<option value="{{ ref.id }}">{{ ref }}</option>{% endfor %}</select>
+        {% for ref in referents %}<option value="{{ ref.id }}">{{ ref }} ({{ ref.num_refs }})</option>{% endfor %}</select>
     </div>
     <div id="buttons_div"><input id="valid_training" type="button" value="Valider ce stage"></div>
     </form>