* Overriding TimeStampedModel's save() method
to update modified field automatically when update_fields argument is used but modified was not given as a parameter.
* fixed a small error in logic
* added tests for new functionality
* - add django 3.0 to the test matrix
- drop six
* add entry in CHANGES
* remove context kwarg
* fix test with DeferredAttribute
* rename StringyDescriptor's name to attname
* Fix flake8
* Drop support for Django 1.11 because the API are not compatibles anymore with Django 3.0
* Try to fix tests.
* Define model for the field mock.
* Simplifies the code.
* Properly mock the field.
* Typo
* Use the new API field name.
* Call it attname
* Grab the field instance from the model.
* Use postgres in travis tests.
* Django 2.0.1 minimum is needed.
* Update Changelog to tell about breaking Django 1.11.
* Update changelog to tell about Django 3.0 support.
* @natim review.
* ✅ Ensure TimeStampedModel modified equals created on initial creation.
Add logic to AutoLastModifiedField which checks to see if the associated created field of the correct cField class type is also present. If the instance has not yet been saved (missing a pk), then set the value to modified to be equal to created.
Fixes#247📚 Update changes and authors list related to changes.
* 🚑 Set TimeStampedModel modified to be equal to created during first save.
If instance does not yet have a pk, before defaulting the last modified to the current time, iterate over the the fields of the model, and instead use whatever value is found in the first occurance of the AutoCreatedField.
Fixes#247
* Move changelog up to unreleased section.
