Replace 'async' keyword with 'is_async' for Queue objects (#977)

* Replaced async keyword with is_async in the Queue class to fix reserved keyword syntax errors in Python 3.7

* Updated tests to use is_async keyword when instantiating Queue objects

* Updated docs to reference is_async keyword for Queue objects

* Updated tox.ini, setup.py and .travis.yml with references to Python 3.7

1 files changed, 1 insertions, 1 deletions

diff --git a/tox.ini b/tox.ini
index 93a76b9..baeba93 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist=py26,py27,py33,py34,py35,pypy,flake8
+envlist=py26,py27,py33,py34,py35,py36,py37,pypy,flake8
 
 [testenv]
 commands=py.test --cov rq --durations=5 {posargs}