Make ResultSet Enumerable
Make ResultSet Enumerable

Thus you can operate directly on ResultSet objects instead of needing to
call `to_a` on them first all the time:

    class User < ActiveRecord::Base
      reportable :registrations
    end

    stats = User.registrations_report(grouping: :weekly, limit: 12)
    stats.last  # => [Mon, 22 Oct 2012, 12.0]

    # No partial humans :-)
    stats.map { |date, value| [date, value.to_i] }

    # With no block, get an Enumerator
    stats.each  # => #<Enumerator: ...>

saulabs/reportable,kassimhalloyta/reportable