Merge pull request #290 from cclauss/patch-1

Travis CI: Add Python 3.7 to the testing

.travis.yml

@@ -2,6 +2,12 @@ language: python
 python:
   - "3.5"
   - "3.6"
+matrix:
+  include:
+    - python: "3.7"
+      dist: xenial
+  allow_failures:
+    - python: "3.7"
 services:
   - mysql
 env:
@@ -29,4 +35,4 @@ script:
     - coverage run manage.py test
 after_success:
     - coveralls
-    - codecov
+    - codecov