fix readme

README.md

@@ -5,6 +5,6 @@ colorFrom: blue          # Starting color for gradient
 colorTo: green           # Ending color for gradient
 sdk: docker              # Use "docker" for backend API Space, or "streamlit" for frontend Space
 sdk_version: "1.0"       # Leave this as is
-app_file: app.py         # Specify your main app file (e.g., api.py or user_interface.py)
+app_file: api.py         # Specify your main app file (e.g., api.py or user_interface.py)
 pinned: false            # Leave as false unless you want to pin the Space
 ---