Drop support for Python 2.7 and add support for Python 3.7

Author: jordaneb

.travis.yml

@@ -3,9 +3,9 @@ sudo: false
 services:
   - mysql
 python:
-- '2.7'
 - '3.4'
 - '3.6'
+- '3.7'
 env:
 - DJANGO_VERSION=1.8
 - DJANGO_VERSION=1.9

django_dbq/tests.py

@@ -88,7 +88,7 @@ def test_worker_with_queue_name(self):
 class WorkerProcessDoWorkTestCase(TestCase):
 
     def setUp(self):
-        super(WorkerProcessDoWorkTestCase, self).setUp()
+        super().setUp()
         self.MockWorker = mock.MagicMock()
         self.MockWorker.queue_name = 'default'
         self.MockWorker.rate_limit_in_seconds = 5