Add test runs on Python 3.7 and 3.8.

.travis.yml

@@ -1,12 +1,14 @@
 language: python
 cache: pip
 python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
-  - "3.6"
-  - "pypy"
-  - "pypy3"
+  - 2.7
+  - 3.4
+  - 3.5
+  - 3.6
+  - 3.7
+  - 3.8
+  - pypy
+  - pypy3
 install:
   - pip install tox
 script:

setup.py

@@ -43,6 +43,7 @@ setuptools.setup(
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
+        'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: Implementation :: CPython',
         'Programming Language :: Python :: Implementation :: PyPy',
     ],

tox.ini

@@ -1,6 +1,6 @@
 # to run for a specific environment, use ``tox -e ENVNAME``
 [tox]
-envlist = py27,py34,py35,py36,pypy,pypy3
+envlist = py27,py34,py35,py36,py37,py38,pypy,pypy3
 
 [testenv]
 deps =