mongo ruby driver mapreduce

test.rb

require 'rubygems'
require 'mongo'

def db
    $db ||= Mongo::Connection.new("localhost", 27017).db("ruby-mongo-examples")
end

def zips
    $zips ||= db.collection("test")
end

class Chart
    @@reduce_count = "function(key, values) { " +
                    "var sum = 0; " +
                    "values.forEach(function(f) { " +
                    " sum += f.count; " +
                    "}); " +
                    "return {count: sum};" +
                "};"

    def self.zip_counts
        @map = "function() { emit(this.zip, {count: 1}); }"
        @reduce = @@reduce_count
        #@results = logs.map_reduce(@map, @reduce,{'query'=> {"zip" => "14850"}})
        @results = zips.map_reduce(@map, @reduce)
    end
end

@s = Chart.zip_counts

@s.find({'value.count' => {'$gte' => 60}}).sort('value.count',-1).to_a.each do |f|
    puts "#{f['_id']} : #{f['value']['count']}"
end