List Python 3.8 support (#541)

* Add Python 3.8 to Travis

* Add Python 3.8 to Tox

* Add Python 3.8 trove classifier

* List Python 3.8 as supported in the README

4 files changed, 5 insertions, 2 deletions

diff --git a/.travis.yml b/.travis.yml
index e51b2e0..6babe1d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -10,6 +10,8 @@ matrix:
     - python: pypy3
     - python: 3.7
       dist: xenial
+    - python: 3.8
+      dist: xenial
     - python: nightly
       dist: xenial
 # TODO: https://bugs.python.org/issue40334
diff --git a/README.rst b/README.rst
index ca802a8..fb13fdf 100644
--- a/README.rst
+++ b/README.rst
@@ -9,7 +9,7 @@ parsing the source file, not importing it, so it is safe to use on
 modules with side effects.  It's also much faster.
 
 It is `available on PyPI <https://pypi.org/project/pyflakes/>`_
-and it supports all active versions of Python: 2.7 and 3.4 to 3.7.
+and it supports all active versions of Python: 2.7 and 3.4 to 3.8.
 
 
 
diff --git a/setup.py b/setup.py
index 5e2088e..e4d709d 100755
--- a/setup.py
+++ b/setup.py
@@ -58,6 +58,7 @@ 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",
         "Topic :: Software Development",
diff --git a/tox.ini b/tox.ini
index f2256c8..7365833 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
 skip_missing_interpreters = True
 envlist =
-    py27,py34,py35,py36,py37,pypy,pypy3
+    py27,py34,py35,py36,py37,py38,pypy,pypy3
 
 [testenv]
 deps = flake8==3.6.0