Use lists to store arrays in Redis

[evanp]

For Redis, we should probably store Javascript arrays as Redis lists.

This will make our append() and prepend() methods atomic and just damn better.

However, it'll make other access pretty crummy. There don't seem to be give-me-the-whole-list methods in Redis lists, see:

http://redis.io/commands#list

Might not be worth it.

Copied from https://github.com/evanp/databank/issues/17

[Kelym]

List (linked list) in redis provide fast access on head and tail, but it can be too slow to access the middle. Though theoretically a linked list can provide a fast iteration through the whole list, redis doesn't seem to provide this kind or method. So, it seems more practical to use sorted set to store arrays ( one array[]=XX actually has two properties: value + order.) .