Composite primary key errors

[shainegordon]

"Reopening" this as this does seem to be an issue, or it's a misunderstanding.

Using a standard reference implementation of composite keys, you'll get an error when calling Add on an Entity in the DBContext:

InvalidOperationException: Unable to track an entity of type 'Client' because its primary key property 'TenantId' is null.

I have created a PR/fork of the sample project that can reproduce this issue: https://github.com/Finbuckle/Finbuckle.MultiTenant/pull/834