Do not display archived students in attribution view

stages/views.py

@@ -149,12 +149,13 @@ def section_classes(request, pk):
 
 def period_students(request, pk):
     """
-    Return all students from period's section and level,
+    Return all active students from period's section and level,
     with corresponding Training if existing (JSON)
     """
     period = get_object_or_404(Period, pk=pk)
-    students = Student.objects.filter(klass__section=period.section, klass__level=period.relative_level
-                             ).order_by('last_name')
+    students = Student.objects.filter(
+        archived=False, klass__section=period.section, klass__level=period.relative_level
+        ).order_by('last_name')
     trainings = dict((t.student_id, t.id) for t in Training.objects.filter(availability__period=period))
     data = [{
         'name': unicode(s),