Add wsgi.py to be able to serve it in test deployment

helloworld/wsgi.py

+"""
+WSGI config for helloworld project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+"""
+
+import os
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "helloworld.settings")
+
+from django.core.wsgi import get_wsgi_application
+application = get_wsgi_application()