This resolves GR-70.

It also addresses the part of GR-52 regarding getting notified of your own system’s changes.
Update structure.sql to make travis happy
Update structure.sql to make travis happy
Add param doc
Improve spec.
Turn owned_by back into a class method
Merge pull request #44 from CruGlobal/GR-70__improve_security_model

This resolves GR-70.