Update README with 'not implemented yet'

Author: jbonnet

son-gtklic/README.md

@@ -1,2 +1,4 @@
 # [SONATA](http://www.sonata-nfv.eu)'s Gatekeeper License Management micro-service
 [![Build Status](http://jenkins.sonata-nfv.eu/buildStatus/icon?job=son-gkeeper)](http://jenkins.sonata-nfv.eu/job/son-gkeeper)
+
+This is the folder of the **License Management** micro-service. This micro-service is used by the [`Gatekeeper API`](https://github.com/sonata-nfv/son-gkeeper/son-gtkapi) and has not yet been developed.