searchable.rb

    module Searchable

      def self.searchable_fields
        []
      end

      def self.included(klass)
        klass.named_scope :by_search, lambda {|q, options|
          if q.present?
            search_text = [klass.searchable_fields].flatten.collect {|f|
              scoped_name = (f =~ /\./ ? f : "#{klass.table_name}.#{f}")
              "#{scoped_name} ILIKE :q"
            }.join(' OR ')
            {:conditions => [search_text, {:q => "%#{q}%"}]}.merge(options)
          else
            {}
          end
        }
      end

    end