Update 'README.md'

Add information about simple authentication.

README.md

@@ -1,2 +1,43 @@
 # nginx-rtmp-docker
 
+## simple authentication
+
+**nginx.conf:**
+```
+worker_processes auto;
+rtmp_auto_push on;
+
+events {}
+
+http {
+    server {
+        listen 80;
+
+        location /auth {
+            if ($arg_pw = 'password') {
+                return 200;
+            }
+            return 403;
+        }
+    }
+}
+
+rtmp {
+    server {
+        listen 1935;
+        listen [::]:1935;
+
+        # 'get' to use $arg_ for auth
+        notify_method get;
+
+        application live {
+            live on;
+            record off;
+
+            on_publish http://127.0.0.1/auth;
+            on_play http://127.0.0.1/auth;
+        }
+    }
+}
+
+```