Update user model logic for Ember Inspector.
Update user model logic for Ember Inspector.

Fixes #2921.

kevinansfield/Ghost-Admin,kevinansfield/Ghost-Admin,JohnONolan/Ghost-Admin,TryGhost/Ghost-Admin,TryGhost/Ghost-Admin,JohnONolan/Ghost-Admin,acburdine/Ghost-Admin,airycanon/Ghost-Admin,dbalders/Ghost-Admin,acburdine/Ghost-Admin,dbalders/Ghost-Admin,airycanon/Ghost-Admin