add celery background tasks and redis server for celery, also modify django to use redis instead of postgres for caching for speed improvement and alleviating sql traffic

src/pkmntrade_club/django_project/__init__.py

@@ -0,0 +1,5 @@
+# This will make sure the app is always imported when
+# Django starts so that shared_task will use this app.
+from .celery import app as celery_app
+
+__all__ = ('celery_app',)