Update README.md

Author: Chris Wiechmann

README.md

@@ -15,7 +15,7 @@ Once the data is indexed by Elasticsearch it can be used by different clients. T
 
 ## Option 1 - Using the existing Traffic-Monitor
 One option is to use the existing API-Gateway Traffic-Monitor. That means, you use the same tooling as of today, but the underlying implementation of the Traffic-Monitor API is now pointing to Elasticsearch instead of the internal OPSDB hosted by each API-Gateway instance. This improves performance damatically, as Elasticsearch can scale across multiple machines if required and other dashboards can be created for instance with Kibana.  
-The glue between Elasticsearch and the API-Gateway Traffic-Monitor is an API-Builder project, that is exposing the same Traffic-Monitor API, but it is implemented using Elasticsearch instead of the OPSDB. The API-Builder is available as a ready to use Docker-Image and preconfigured in the docker-compose file.  
+The glue between Elasticsearch and the API-Gateway Traffic-Monitor is an [API-Builder project](./elk-traffic-monitor-api), that is exposing the same Traffic-Monitor API, but it is implemented using Elasticsearch instead of the OPSDB. The API-Builder is available as a ready to use Docker-Image and preconfigured in the docker-compose file.  
 Optionally you can import the API-Builder API into your API-Management system to apply additional security and by that secure access to your Elasticsearch instance.  
 
 Finally, the Admin-Node-Manager has to be configured to use the API-Builder API instead of the internal implementation.