Cleaning up application categories.

Change-Id: Id3c937323123b6089cedf7b31cd01151f6aca8e1
diff --git a/apps/yang-gui/BUCK b/apps/yang-gui/BUCK
index 13d92d9..7e971f4 100644
--- a/apps/yang-gui/BUCK
+++ b/apps/yang-gui/BUCK
@@ -14,7 +14,7 @@
 
 onos_app (
     title = 'YANG Runtime GUI',
-    category = 'Utility',
+    category = 'GUI',
     url = 'http://onosproject.org',
     description = 'Adds GUI extension that allows the operator to view the list of currently ' +
         'registered YANG models, and their YANG sources. It also provides means for compiling ' +