Database caching

[t-persson]

Description

I would like to see some database caching so that events that are requested multiple times return faster and we don't hammer MongoDB as much.

Motivation

Faster lookups and a more efficient service.

Exemplification

Multiple users are interested in a specific Artifact event, instead of looking for that event in all collections for each user, it can be looked up once and returned to every user.

Benefits

Gotta go fast

Possible Drawbacks

The problem with caches is if the data goes stale, but since Eiffel does not allow modification of sent events this should never be a problem