Update server.py

server.py

@@ -19,6 +19,7 @@ except ImportError:
     Features, Value = None, None
 
 STORAGE_BACKEND_CONFIG = os.getenv("STORAGE_BACKEND", "JSON").upper()
+DATASET_BACKEND=os.getenv("DATASET_BACKEND")
 HF_DATASET_REPO = os.getenv("HF_DATASET_REPO")
 HF_TOKEN = os.getenv("HF_TOKEN")
 HF_BACKUP_THRESHOLD = int(os.getenv("HF_BACKUP_THRESHOLD", 10))