update readme

Author: splitbrain

README.md

@@ -1,4 +1,10 @@
-# DokuWiki Extension Mirror Script
+# DokuWiki CodeSearch
+
+The CodeSearch service is powerd by [OpenGrok](https://opengrok.github.io/OpenGrok/), an open source source code search and cross reference engine. A PHP script (see below) uses the DokuWiki plugin repository API to periodically download all available DokuWiki plugins and templates, and indexes them with OpenGrok.
+
+The service is hosted at https://codesearch.dokuwiki.org/ and is open to everyone.
+
+## DokuWiki Extension Mirror Script
 
 This tool will download all available DokuWiki plugins/templates and extract them to `data/src`. This is useful for DokuWiki developers who need to check if a certain DokuWiki function is used by any plugins.
 
@@ -8,13 +14,13 @@ Downloaded archives are kept in `data/meta` when extraction fails to ease debugg
 
 The tool uses the DokuWiki [plugin repository API](https://github.com/splitbrain/dokuwiki-plugin-pluginrepo/blob/master/README-API) and will only download a plugin again when it's version changes.
 
-## Setup
+### Setup
 
 Just use composer:
 
     composer install
 
-## Running
+### Running
 
 Call the mainfile: