Update app.py

app.py

@@ -34,7 +34,9 @@ vector_store = InMemoryVectorStore(embedding=embeddings)
 
 
 def upload_pdf(file):
-    """Save uploaded PDF file"""
+    """Ensure directory exists and save the uploaded file."""
+    os.makedirs(pdfs_directory, exist_ok=True)
+    
     with open(pdfs_directory + file.name, "wb") as f:
         f.write(file.getbuffer())