add function to retrieve stories inside a geo fence to users_routes

I'm not sure you need a `return` here. Just  `Story.find({})...`
Also, I'm pretty sure it'll be more performant to include the query conditions within the find() conditions object instead of appending where clauses. (I think doing a find({}) returns the whole collection and then appending .where(...) filters that collection, whereas using the conditions object returns only those documents that match the conditions).