The activities in catalog workflow should be logged into db. Then these activities can be tracked properly. 

We will try to minmic the logging mechanism for bug activities in BZ.

1) All fields which need be logged should be defined in a table, like BZ's 'fielddef'
2) Define a new table for workflow activities, like BZ's 'bugs_activity'

3) overwrite the 'update' function in workflow objects, add the codes for saving workflow activities.