Cache

[z64]

Player objects tell us when the data in that request response may be stale via the @next_update attribute.

Considering the the API rate limit and how long a Player can go without being updated, we should provide a cache that will return cached Players that we know are still up-to-date, or make an API request on a cache miss or stale data (Time.now > player.next_update)

We may work other data objects into this cache if only for consistency, but at the least we should provide one specifically for Players, since it's probably the hottest path anyone will implement.

[z64]

Do we want to implement this for v1.0? It can wait if we want.