Dumping empty tables doesn't empty them when loading

[tovodeverett]

It appears that yaml_db doesn't dump empty tables, which means that it doesn't know to truncate them when loading. This was definitely unexpected. It is fairly easy to resolve, but before I create a pull request (including extending the test suite to validate the behavior), I'd like to know if there's a consensus that this behavior should be changed. In case anyone else wants my monkey-patch in the interim, here is my monkey patch for 0.2.3:

module SerializationHelper
  class Load
    def self.load_records(table, column_names, records)
      if column_names.nil?
        return
      end
      columns = column_names.map{|cn| ActiveRecord::Base.connection.columns(table).detect{|c| c.name == cn}}
      quoted_column_names = column_names.map { |column| ActiveRecord::Base.connection.quote_column_name(column) }.join(',')
      quoted_table_name = SerializationHelper::Utils.quote_table(table)
      (records || []).each do |record|
        quoted_values = record.zip(columns).map{|c| ActiveRecord::Base.connection.quote(c.first, c.last)}.join(',')
        ActiveRecord::Base.connection.execute("INSERT INTO #{quoted_table_name} (#{quoted_column_names}) VALUES (#{quoted_values})")
      end
    end
  end

  class Dump
    def self.dump_table(io, table)
      dump_table_columns(io, table)
      dump_table_records(io, table)
    end
  end
end

The modification to SerializationHelper::Load::load_records is to substitute an empty array for records if the latter is missing. The modification to SerializationHelper::Dump.dump_table is to eliminate the first line that returns if the table has no records.