Changed to only get authorized models.
Changed to only get authorized models.

Added
=====

* New AuthorizationError class thrown when trying to view/edit
  a model that is not public or not owned by the current user.

Changed
=======

* get_model function now raises an error when trying to get a model
  that is the user is not authorized to get.

mcflugen/wmt-rest,mcflugen/wmt-rest