passing an ActiveRecord object to `exists?` is deprecated.

Pass the id of the object to the method by calling `.id` on the AR
object.
passing an instance of an AR object to `find` is deprecated

please pass the id of the AR object by calling `.id` on the model first.
Merge branch 'master' into adequaterecord

* master:
  passing an instance of an AR object to `find` is deprecated
  passing an ActiveRecord object to `exists?` is deprecated.
add the deprecation to adequate record too