class Person
  include Mongoid::Document
  field :name, :type => String
  field :age, :type => Integer

  validates_numericality_of :age
end


p = Person.new(:age => 35)
p.save!

p => { "_id" : ObjectId("4f4845e6759b51801a000582"), "age" : 35 }

p.age = "infinity"
if p.save
	p.update_attribute(:name, "Alex")
else
	p.update_attribute(:name, "Hooligan")
end

p => { "_id" : ObjectId("4f4845e6759b51801a000582"), "age" : "infinity", "name" : "Hooligan" }