feat: add websocket

main.py

@@ -220,7 +220,7 @@ async def websocket_endpoint_student(websocket: WebSocket, user_id: str):
         client_settings=CHROMA_SETTINGS,
     )
 
-    RETRIEVER = DB.as_retriever()
+    RETRIEVER = DB_USER.as_retriever()
 
     QA = RetrievalQA.from_chain_type(
         llm=LLM,
@@ -267,7 +267,7 @@ async def websocket_endpoint_room(websocket: WebSocket, room_id: str, user_id: s
         client_settings=CHROMA_SETTINGS,
     )
 
-    RETRIEVER = DB.as_retriever()
+    RETRIEVER = DB_ROOM.as_retriever()
 
     QA = RetrievalQA.from_chain_type(
         llm=LLM,