Merge pull request #1587 from hauke96/master

Update gunicorn to 19.8.0 fixing #1586

Author: pierotofy

requirements.txt

@@ -20,7 +20,7 @@ djangorestframework-guardian==0.3.0
 drf-nested-routers==0.11.1
 funcsigs==1.0.2
 futures==3.1.1
-gunicorn==19.7.1
+gunicorn==19.8.0
 itypes==1.1.0
 kombu==4.6.7
 Markdown==3.3.4