Starting to add membership management messages.
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/MessageSubject.java b/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/MessageSubject.java
index bf86c5b..c7badf2 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/MessageSubject.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/cluster/messaging/MessageSubject.java
@@ -8,8 +8,11 @@
     /** Represents a first greeting message. */
     HELLO,
 
-    /** Signifies node's intent to leave the cluster. */
-    GOODBYE,
+    /** Signifies announcement about new member. */
+    NEW_MEMBER,
+
+    /** Signifies announcement about leaving member. */
+    LEAVING_MEMBER,
 
     /** Signifies a heart-beat message. */
     ECHO