Fix typo that in .env.sample which stopped proper configuration of production server (#111)

Author: vaibhavs-mishra

.env.sample

@@ -14,4 +14,4 @@ DJANGO_SUPERUSER_PASSWORD=admin
 # Uncomment for development
 #CELERY_BROKER_URL=redis://localhost:6379/0
 # Uncomment for production
-#CELERY_BROKER_URL=redis://reids:6379/0
+#CELERY_BROKER_URL=redis://redis:6379/0