gistfile1.rb

# FUCK NO
class Person
  include Mongoid::Document
  field :athing, :type => String, :default => "Something"
  validates_format_of :athing, :with => /[A-Za-z]/
end

# HELL YES

class Person
  include Mongoid::Document
  string :athing do
    default "Someting"
    format /[A-Za-z]/
  end
end