TTL (time-to-live) for expiring objects

[christiansmith]

Some objects stored in the database should have a TTL associated with them. For example, access tokens, authorization codes, etc.

[adalinesimonian]

We could check at boot-time for expired objects that need to be removed in the database. Then, as the server is running, when objects with TTLs are created, they could be thrown in a queue for deletion (#129).

[adalinesimonian]

In #171, we're using keys instead of hashes, and so we're able to take advantage of Redis' EXPIREAT command.