Test on Django 2.1

Author: kevin-brown

tox.ini

@@ -3,6 +3,8 @@ envlist =
     flake8
     py36-django20-drf{37,38,39}
     py37-django20-drf{39}
+    py36-django21-drf{38,39}
+    py37-django21-drf{39}
 
 [testenv]
 commands =
@@ -12,6 +14,7 @@ deps =
     pytest-cov
     pytest-django
     django20: Django==2.0.*
+    django21: Django==2.1.*
     drf37: djangorestframework==3.7.*
     drf38: djangorestframework==3.8.*
     drf39: djangorestframework==3.9.*