ErwinM/acts_as_tenant — pull request #73 by sadjow (2014-03-17 21:02:02+00:00)
Title: Make tenant attribute immutable only if the current tenant is set.

It's need to make tenant attribute immutable only if the current tenant
is set. Sometimes a system area doesn't have a tenant set, needs to edit
that attribute. An example:

When you are in a administrative area and a tenant is not set. You need be able
to edit the tenant attribute.