update README

Author: TimothyYe

README.md

@@ -32,6 +32,7 @@
 - [Configuration](#configuration)
   - [Overview](#overview)
   - [Configuration file format](#configuration-file-format)
+  - [Dynamic loading of configuration](#dynamic-loading-of-configuration)
   - [Configuration properties](#configuration-properties)
   - [Update root domain](#update-root-domain)
   - [Configuration examples](#configuration-examples)