Mention R client library in Readme

Change-Id: I5415df5d2cba5ee74dffc71881e3fe0812e04759
diff --git a/README.md b/README.md
index 3b8c662..e8f1b06 100644
--- a/README.md
+++ b/README.md
@@ -146,6 +146,10 @@
 docker run -d=false -p 3000:3000 --rm -v $(pwd)/config:/config:z ids-kl/derekovecs
 ```
 
+## Client library for R
+
+See [rderekovecs](https://korap.ids-mannheim.de/gerrit/plugins/gitiles/IDS-Mannheim/rderekovecs).
+
 ## News
 
 See [Changelog](./Changelog.md)