Map User/Interests to Interest/Users

Personalizr MapReduce 1

def self.update_map
		map = 'function() {' +
			'for (var i in this.interests) {' +
				'if (this.interests[i]._id != null) {' +
					'emit(this.interests[i]._id, {"users": this.facebook_id, "count": 1});' +
				'}' +
			'}' +
		'}';
		reduce = 'function(key, emits) {' +
				'var all_users = Array();	var count = 0;' +
				'for(var i in emits) {' +
					'all_users = all_users.concat(emits[i].users);' +
					'count += emits[i].count;' +
				'}' +
				'return {"users": all_users, "count": count};}';
		User.collection.map_reduce(map, reduce,{:query => {:is_user => true}, :out => "interest_maps"}) 
	end