Update app.py

app.py

@@ -1,3 +1,8 @@
+try:
+    import detectron2
+except:
+    import os 
+    os.system('pip install git+https://github.com/facebookresearch/detectron2.git')
 import streamlit as st
 from detectron2.config import get_cfg
 from detectron2.engine import DefaultPredictor