Put example key in default config.

Daniel Abercrombie · Daniel Abercrombie · commit a437b251ae6d · 2018-11-29T10:24:25.000-05:00
diff --git a/workflowwebtools/default/config.yml b/workflowwebtools/default/config.yml
@@ -81,3 +81,4 @@ cluster:
 cache_refresh:
   errors: 345600
 workspace: '.'
+refresh_period: 15
