Delete related videos when a participation got deleted

apps/participation/apps.py

@@ -1,5 +1,5 @@
 from django.apps import AppConfig
-from django.db.models.signals import post_save, pre_save
+from django.db.models.signals import post_save, pre_delete, pre_save
 
 
 class ParticipationConfig(AppConfig):

apps/participation/signals.py

@@ -23,3 +23,10 @@ def update_mailing_list(instance: Team, **_):
             for coach in instance.coachs.all():
                 get_sympa_client().subscribe(coach.user.email, f"equipe-{instance.trigram.lower()}", False,
                                              f"{coach.user.first_name} {coach.user.last_name}")
+
+
+def delete_related_videos(instance: Participation, **_):
+    if instance.solution:
+        instance.solution.delete()
+    if instance.synthesis:
+        instance.synthesis.delete()