Update changelog

changelog

 0.1: initial skeleton
 0.2: use celery for task management
 0.3: basic opsdb, alarmsdb coms & test api
-0.4: added some further sample resources
\ No newline at end of file
+0.4: added some further sample resources
+0.5: added meaningful alarmsdb demo method
+     added snmp index to interface data to support sensu, prometheus
+     increased unit test coverage to 78%
\ No newline at end of file