add DbMgr

Change-Id: I799f6a066ef60ecd42d64de7d8d04be8996564ed
diff --git a/src/zone.cpp b/src/zone.cpp
index 6f859a4..3c7fd1a 100644
--- a/src/zone.cpp
+++ b/src/zone.cpp
@@ -18,10 +18,13 @@
  */
 
 #include "zone.hpp"
+#include "logger.hpp"
 
 namespace ndn {
 namespace ndns {
 
+NDNS_LOG_INIT("Zone")
+
 Zone::Zone()
   : m_id(0)
   , m_ttl(3600)