(feat): add full compatibility with Django 2.x

- fix Django 1.10+ deprecation of the Manager's use_for_related_fields
  by replacing with Meta.base_manager_name on the Model
  - add a check for Django < 1.10 so that this maintains backward
    compatibility while not giving warnings for newer versions

- (docs): change docs to note this
- (pub): add Django 2.1 classifier

README.md

@@ -27,8 +27,7 @@ It is expected that you already have Django installed
 _This was originally used in an older Django 1.5 codebase with Python 2.7._
 
 Should work with Django 1.4-1.9 with Python 2.7-3.x.
-- Likely works with Django 1.10 and 1.11, though not 100% sure that [`._meta.fields` usage works the same way in these](https://docs.djangoproject.com/en/2.0/ref/models/meta/#migrating-old-meta-api).
-- Will have some problems with Django 2.0 as the Manager's [`use_for_related_fields` has been removed](https://docs.djangoproject.com/en/2.0/releases/2.0/#features-removed-in-2-0).
+- Likely works with Django 1.10-2.x, though not 100% sure that [`._meta.fields` usage works the same way in these](https://docs.djangoproject.com/en/2.0/ref/models/meta/#migrating-old-meta-api).
 - `2to3` shows that there is nothing to change, so should be compatible with Python 3.x
 - Likely works with Django 0.95-1.3 as well; pre 0.95, the Manager API didn't exist
 - Have not confirmed if this works with earlier versions of Python.

serializable.py

@@ -14,8 +14,10 @@ def serialize(self, *args):
 
 class SerializableManager(models.Manager):
     """Implements table-level serialization via SerializableQuerySet"""
-    # when queried from a related Model, use this Manager
-    use_for_related_fields = True
+    # backward compatibility for Django < 1.10
+    if django.VERSION < (1, 10):
+        # when queried from a related Model, use this Manager
+        use_for_related_fields = True
 
     def get_queryset(self):
         return _SerializableQuerySet(self.model)
@@ -44,6 +46,8 @@ class SerializableModel(models.Model):
 
     class Meta:
         abstract = True
+        # when queried from a related Model, use this Manager
+        base_manager_name = 'SerializableManager'
 
     def serialize(self, *args, **kwargs):
         """

setup.py

@@ -43,6 +43,7 @@
         'Framework :: Django :: 1.10',
         'Framework :: Django :: 1.11',
         'Framework :: Django :: 2.0',
+        'Framework :: Django :: 2.1',
     ],
     keywords=('django serializer serializers serializer-django serialize ' +
               'json dict queryset model modelmanager full wadofstuff'),