Fix Travis CI builds

.travis.yml

@@ -1,26 +1,20 @@
 language: python
-python: "3.6"
 
-env:
+python:
+  - '2.7'
+  - '3.4'
+  - '3.5'
+  - '3.6'
+
 matrix:
-    - TOXENV=py27-django18
-    - TOXENV=py34-django18
-    - TOXENV=py35-django18
-    - TOXENV=py27-django19
-    - TOXENV=py34-django19
-    - TOXENV=py35-django19
-    - TOXENV=py27-django110
-    - TOXENV=py34-django110
-    - TOXENV=py35-django110
-    - TOXENV=py27-django111
-    - TOXENV=py34-django111
-    - TOXENV=py35-django111
-    - TOXENV=py36-django111
-    - TOXENV=flake8
-    - TOXENV=isort
+  include:
+    - python: '3.6'
+      env: TOXENV=flake8
+    - python: '3.6'
+      env: TOXENV=isort
 
 install:
-    - pip install coverage coveralls tox
+  - pip install coverage coveralls tox tox-travis
 
 script:
   - tox

tox.ini

@@ -1,7 +1,8 @@
 [tox]
 envlist =
-    py{27,34,35}-django{18,19,110}
-    py{27,34,35,36}-django111,
+    django{18,19,110}-py{27,34,35},
+    django111-py{27,34,35,36},
+    django20-py{34,35,36},
     cov_combine,
     flake8,
     isort
@@ -12,6 +13,7 @@ deps =
     django19: django>=1.9,<1.10
     django110: django>=1.10,<1.11
     django111: django>=1.11,<2.0
+    django20: django>=2.0,<2.1
     coverage
     mock ; python_version < "3.0"
 usedevelop = True