add_index_length

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 748
      def add_index_length(option_strings, column_names, options = {})
        if options.is_a?(Hash) && length = options[:length]
          case length
          when Hash
            column_names.each {|name| option_strings[name] += "(#{length[name]})" if length.has_key?(name) && length[name].present?}
          when Integer
            column_names.each {|name| option_strings[name] += "(#{length})"}
          end
        end

        return option_strings
      end