class Birthday
  include Mongoid::Document
  field :title
  field :date, type: Date
  embedded_in :owner, inverse_of: :birthdays

  def self.each_day(start_date, end_date)
    groups = only(:date).asc(:date).where(:date.gte => start_date, :date.lte => end_date).group
    groups.each do |date, group|
      yield(date, group)
    end
  end
end