Add update api

docs/api/v2/README.md

@@ -1,7 +1,9 @@
-# Sync API v2 (Draft)
+# External API v2 (Draft)
 
 The **News app** offers a RESTful API which can be used to sync folders, feeds and items. The API also supports [CORS](https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS) which means that you can access the API from your browser using JavaScript.
 
+In addition, an updater API is exposed which is able to run feed updates in parallel using a REST API or ownCloud console API.
+
 ## API Stability Contract
 
 The API level will **change** if the following occurs: