Monkeypatch sample functionality into ActiveRecord

sample.rb

class ActiveRecord::Base     

  def self.sample(count=nil)
    all_ids = (1..self.count).to_a
    if count
      ids = all_ids.sample(count)
      self.where(id: ids)
    else
      id = all_ids.to_a.sample
      self.find(id)
    end
  end

end