Sorting by two fields mongoid
===

I have an object Report that contains two integer fields: Month and Year.
I need to sort it by "date"

    Report.desc(:year).desc(:month).each do |a|
    puts a.year.to_s + " " + a.month.to_s
    end

results:

    2011 12
    2011 11
    2012 7
    2012 6
    2012 5
    2012 4
    2012 3
    2012 2
    2012 1


While I would think to get

    2012 7
    2012 6
    2012 5
    2012 4
    2012 3
    2012 2
    2012 1
    2011 12
    2011 11

What am I doing wrong?
