fix:rag serve error

dbgpt/client/schemas.py

@@ -1,4 +1,5 @@
 from datetime import datetime
+from enum import Enum
 from typing import Dict, List, Optional, Union
 
 from fastapi import File, UploadFile
@@ -60,6 +61,15 @@ class ChatCompletionRequestBody(BaseModel):
     )
 
 
+class ChatMode(Enum):
+    """Chat mode"""
+
+    CHAT_NORMAL = "chat_normal"
+    CHAT_APP = "chat_app"
+    CHAT_AWEL_FLOW = "chat_flow"
+    CHAT_KNOWLEDGE = "chat_knowledge"
+
+
 class SpaceModel(BaseModel):
     """name: knowledge space name"""