chore: updated readme

README.md

@@ -22,3 +22,15 @@ tesseract-ocr
 ### Secure
 
 This service is private application, requires user name and password (ref. secret variable `USERNAME` & `PASSWORD`).
+
+```python
+def auth(username, password):
+    u = os.environ.get('USERNAME')
+    p = os.environ.get('PASSWORD')
+    return (username == u and password == p)
+
+with gr.Blocks() as demo:
+    # setup layout here...
+
+demo.launch(auth=auth)
+```