Add default sendfile backend to use in production in comment

coin/settings.py

@@ -120,6 +120,7 @@ PRIVATE_FILES_ROOT = os.path.join(BASE_DIR, 'smedia/')
 
 # Backend to use when sending private files to client
 # In production, must be sendfile.backends.xsendfile with Apache xsend file mod
+# Or failing xsendfile, use : sendfile.backends.simple
 # https://github.com/johnsensible/django-sendfile
 SENDFILE_BACKEND = 'sendfile.backends.development'