configure mongo indexes

[mblakele]

As the database grows larger, indexes help keep some of the queries lively. In the long run it would be nice if leselys configured these automatically. Meanwhile it's easy enough to set them up manually.

I think these are a good start:

$ mongo
use leselys
db.feeds.ensureIndex({feed_id:"hashed"})
db.feeds.ensureIndex({guid:"hashed"})