Added missing workflow mappings

Story: https://www.pivotaltracker.com/story/show/74589430

I confirmed this commit fixes the caching issue (http://grc-ux.appspot.com has this commit included in it's current deployment).
```
-    mapping('CycleTaskGroupObject', 'object'),
+    mapping('CycleTaskGroupObject', 'task_group_object'),
+    mapping('CycleTaskGroupObject', 'cycle_task_group'),
```

Technically, task_group_object isn't needed, because the reverse relationship is not included in the TaskGroupObject resource, but completeness.