Restructured sample project for Django 2.

Refactored database and changed "app" to "samples" so name didn't conflict with "AppConfig".
Replaced deprecated assignment_tag with simple_tag.
Updated unit tests.

adminsortable/__init__.py

@@ -1,4 +1,4 @@
-VERSION = (2, 1, 1)
+VERSION = (2, 1, 2)
 DEV_N = None
 
 

adminsortable/templatetags/django_template_additions.py

@@ -76,7 +76,7 @@ def dynamic_regroup(parser, token):
     return DynamicRegroupNode(target, parser, expression, var_name)
 
 
-@register.assignment_tag
+@register.simple_tag
 def get_django_version():
     version = django.VERSION
     return {'major': version[0], 'minor': version[1]}