gistfile1.rb

class User < ActiveRecord::Base
  # here use after create callback
  # http://api.rubyonrails.org/classes/ActiveRecord/Callbacks.html
  after_create :create_facebookdata

  def create_facebookdata
    # do some stuff here
    self.facebookdata = Facebookdata.new
    self.facebookdata.save!
  end

end