Update app.py

app.py

@@ -74,7 +74,7 @@ class RAGConfig:
     chunk_size: int = 500
     chunk_overlap: int = 100
     retriever_k: int = 3
-    # persist_directory: str = "./chroma_db"
+    persist_directory: str = "./chroma_db"
 
 class AdvancedRAGSystem:
     """Advanced RAG System with improved error handling and type safety"""