Adding gunicorn dependency

server/setup.py

@@ -1,8 +1,12 @@
+import sys
 from setuptools import setup, find_packages
 
 with open('requirements.txt', mode='r') as f:
     requirements = [package for package in f]
 
+    if sys.platform != 'win32':
+        requirements.append("gunicorn")
+
 with open('dev_requirements.txt', mode='r') as f:
     dev_requirments = [package for package in f]