Merge pull request encode#2319 from maryokhin/master

Assert fields in `exclude` are model fields

Author: lovelydinosaur

rest_framework/serializers.py

@@ -880,6 +880,10 @@ def get_fields(self):
  exclude = getattr(self.Meta, 'exclude', None)
  if exclude is not None:
  for field_name in exclude:
+ assert field_name in fields, (
+ 'The field in the `exclude` option must be a model field. Got %s.' %
+ field_name
+ )
  fields.remove(field_name)
 
  # Determine the set of model fields, and the fields that they map to.