title: Couch DB bulk update using handlers
body: <p>I'm using CouchDB and I have a situation where there are a bunch of documents keyed on user ids. I would like to be able to send a single query to update a particular field in all these documents. For example when a notification comes in, I'd like each user document to be updated with it by passing in the list of users to whom the notification applies and the notification message.</p>