gistfile1.builder

User.where(:age.gt => 27).sort(:age).all,
User.where(:age.gt => 27).sort(:age.desc).all,
User.where(:age.gt => 27).sort(:age).limit(1).all

class User
  include MongoMapper::Document

  scope :johns, where(:name => 'John')
  scope :bills, :name => 'Bill'
  scope :by_name,  lambda { |name| where(:name => name) }

  def self.by_tag(tag)
    where(:tags => tag)
  end
end