Simple search for all Rails 3.2 ActiveRecord models on any string column(s)

simple_search.rb

class ActiveRecord::Base
  class << self
    def has_simple_search(*attrs)
      raise 'has_simple_search expects at least one attribute' if attrs.empty?
      instance_eval do # because this is ActiveRecord::Base, the class inherits this
        class_attribute :simple_search_fields
        self.simple_search_fields = attrs.flatten
        def simple_search(search_string)
          return find(:all) if search_string.nil? || search_string.blank?
          attrs = self.simple_search_fields
          like_s = attrs.map{|f| "#{self.table_name}.#{f.to_s} REGEXP ?"}.join(' OR ')
          terms = search_string.split(' ').map{|s| Regexp.escape(s.strip)}
          where(Array.new(attrs.count, terms.join('|')).unshift(like_s))
        end
      end
    end
  end
end

Add Support for 3.2 and remove deprecated "write_inheritable_attribute"

That might sound like a basic question. But where do I have to implement it?