Use database for statistics service

This function is limited to full version since lite doesn't support VC.
Since the statistics service accepts corpus query (cq) in general, it
only works for single VC reference.

Change-Id: I326f2de8a48dcd9387163aab8b05357233b47be4
diff --git a/Changes b/Changes
index 0719d14..3e25a0e 100644
--- a/Changes
+++ b/Changes
@@ -1,9 +1,11 @@
 # version 1.0.1
 
 - Add an exception for missing layer.
-- Use database for querying VC statistics.
+- Use database for querying statistics in VC List
 - Fixed statistics conversion.
 - Always update VC statistics at server start
+- Use database for statistics service (limited to full version 
+  and single VC reference)
 
 # version 1.0