NPE bugfix

gms/src/main/java/it/inaf/ia2/gms/controller/JWTWebServiceController.java

@@ -73,6 +73,10 @@ public class JWTWebServiceController {
 
     private String getGroupCompleteName(GroupEntity group, Map<String, String> idNameMap) {
 
+        if ("ROOT".equals(group.getId())) {
+            return group.getName();
+        }
+
         List<String> names = new ArrayList<>();
 
         for (String groupId : group.getPath().split("\\.")) {