  
          field_mapping = {
              models.FloatField: FloatField,
              models.IntegerField: IntegerField,
              models.PositiveIntegerField: IntegerField,
              models.SmallIntegerField: IntegerField,
 
</s> remove         if not model_field.editable:
 </s> add         if isinstance(model_field, models.AutoField) or not model_field.editable: </s> remove         return Field()
 </s> add         return self.get_field(model_field)
            models.AutoField: IntegerField,
  
          field_mapping = {
            models.AutoField: IntegerField,
              models.FloatField: FloatField,
              models.IntegerField: IntegerField,
              models.PositiveIntegerField: IntegerField,
              models.SmallIntegerField: IntegerField,
keep add keep keep keep keep
 PK fields should only be read-only if they are an AutoField.  Fixes #563 
rest_framework/serializers.py