Sorted list insertion and deletion script [WIP]

This is just to stage what I have right now.

(Sorted list)[http://redis.io/topics/data-types#sorted-sets] is relevant to issues #162 and #158. This script makes it easy to maintain the list of featured games (sorted by rank) and the list of pending game queue.

Todo:
- [ ] add deletion script
- [ ] call the scripts through (redis.eval)[http://redis.io/commands/EVAL]