add signal handler to auto-delete video file on Video model deletion

backend/videoflix/content/apps.py

@@ -4,3 +4,6 @@ from django.apps import AppConfig
 class ContentConfig(AppConfig):
     default_auto_field = 'django.db.models.BigAutoField'
     name = 'content'
+    
+    def ready(self):
+        from . import signals

backend/videoflix/content/signals.py

@@ -0,0 +1,14 @@
+from .models import Video
+from django.dispatch import receiver
+from django.db.models.signals import post_delete
+import os
+
+@receiver(post_delete, sender=Video)
+def auto_delete_file_on_delete(sender, instance, **kwargs):
+    """
+    Deletes file from filesystem
+    when corresponding `Video` object is deleted.
+    """
+    if instance.video_file:
+        if os.path.isfile(instance.video_file.path):
+            os.remove(instance.video_file.path)

backend/videoflix/videoflix/settings.py

@@ -51,7 +51,7 @@ INSTALLED_APPS = [
     'rest_framework.authtoken',
     'rest_framework',
     'corsheaders',
-    'content',
+    'content.apps.ContentConfig',
     'users',
 ]