Add continuously optimization

This patch set adds implementation for CONTINUOUS type
of audit.

Change-Id: I5f4ec97b2082c8a6b3ccebe36b2a343fa4a67d19
Implements: blueprint continuously-optimization

watcher/tests/db/utils.py

@@ -62,6 +62,7 @@ def get_test_audit(**kwargs):
         'updated_at': kwargs.get('updated_at'),
         'deleted_at': kwargs.get('deleted_at'),
         'parameters': kwargs.get('parameters', {}),
+        'interval': kwargs.get('period', 3600),
     }