def add(record, analyzer = nil)
      unless Hash === record || Ferret::Document === record
        analyzer = record.ferret_analyzer
        record = record.to_doc 
      end
      ferret_index.add_document(record, analyzer)
    end
def add(record, analyzer = nil)
      unless Hash === record || Ferret::Document === record
        analyzer = record.ferret_analyzer
        record = record.to_doc 
      end
      ferret_index.add_document(record, analyzer)
    end
methods working on a single record
 called from instance_methods, here to simplify interfacing with the
 remote ferret server
 TODO having to pass id and class_name around like this isn't nice

 add record to index
 record may be the full AR object, a Ferret document instance or a Hash