application_controller.rb

class ApplicationController < ActionController::Base
  rescue_from ActiveRecord::StaleObjectError do |exception|
    respond_to do |format|
      format.html {
        correct_stale_record_version
        stale_record_recovery_action
      }
      format.xml  { head :conflict }
      format.json { head :conflict }
    end
  end
  
  protected
  
  def stale_record_recovery_action
    flash.now[:error] = "Another user has made a change to that record "+
      "since you accessed the edit form."
    render :edit, :status => :conflict
  end
end

destinations_controller.rb

class DestinationsController < ApplicationController
  protected
  
  def correct_stale_record_version
    @destination.reload.attributes = params[:destination].reject do |attrb, value|
      attrb.to_sym == :lock_version
    end
  end
end