Run flake8 and black via tox

JIRA: COMPOSE-4108
Signed-off-by: Haibo Lin <hlin@redhat.com>

.gitignore

@@ -12,3 +12,4 @@ tests/_composes
 htmlcov/
 .coverage
 .idea/
+.tox

tox.ini

@@ -1,5 +1,22 @@
+[tox]
+envlist = py27, py36
+
+[testenv]
+deps =
+    flake8
+commands =
+    flake8 pungi pungi_utils setup.py tests/*py
+
+[testenv:py36]
+deps =
+    {[testenv]deps}
+    black
+commands =
+    {[testenv]commands}
+    black --check pungi pungi_utils setup.py tests --exclude tests/_composes
+
 [flake8]
-exclude = doc/*,*.pyc,*.py~,*.in,*.spec,*.sh,*.rst,setup.py
+exclude = doc/*,*.pyc,*.py~,*.in,*.spec,*.sh,*.rst
 filename = *.py
 max-line-length = 88