add createdBy and created to groups
use timestamp type for created and fix doc
add migration script for group creation date
cleanup migration script
Make sure timestamps are integers
Cleaned up group model JSDoc
Merge branch 'groupCreated'

* groupCreated:
  Cleaned up group model JSDoc
  Make sure timestamps are integers
  cleanup migration script
  add migration script for group creation date
  use timestamp type for created and fix doc
  add createdBy and created to groups
Moved group created migration script to   folder in anticipation of the 9.0 release