feat: Update SoundPlayed model to allow nullable user_id

app/__init__.py

@@ -120,6 +120,6 @@ def create_app():
         """Stop services when app context is torn down."""
         if exception:
             scheduler_service.stop()
-            music_player_service.stop_vlc_instance()
+            # music_player_service.stop_vlc_instance()
 
     return app

app/models/sound_played.py

@@ -20,7 +20,7 @@ class SoundPlayed(db.Model):
     user_id: Mapped[int] = mapped_column(
         Integer,
         ForeignKey("user.id"),
-        nullable=False,
+        nullable=True,
     )
     sound_id: Mapped[int] = mapped_column(
         Integer,