remove pytz and change timestamp logic

app.py

@@ -1,5 +1,5 @@
 import os, subprocess, time, pytz
-from datetime import datetime
+from datetime import datetime, timedelta, timezone
 from fastapi import FastAPI
 
 from langchain_community.vectorstores import Chroma
@@ -70,9 +70,9 @@ def rag_with_reranking(query : str):
 def search_text(query):
     """Searches for similar texts."""
 
-    tz = pytz.timezone('Asia/Bangkok')  # GMT+7
-    now = datetime.now(tz)
-    print(f"{now.strftime('%Y-%m-%d %H:%M:%S')}")
+    now_utc = datetime.now(timezone.utc)
+    now = now_utc + timedelta(hours=7)
+    print(now.strftime('%Y-%m-%d %H:%M:%S +07'))
     print(f"Searching for: {query}")
 
     start = time.time()