class ActiveRecord::ConnectionAdapters::SchemaCache

def open(filename)
  FileUtils.mkdir_p(File.dirname(filename))
  File.atomic_write(filename) do |file|
    if File.extname(filename) == ".gz"
      zipper = Zlib::GzipWriter.new file
      yield zipper
      zipper.flush
      zipper.close
    else
      yield file
    end
  end
end