Measurement.define(:dg) do |unit|
  unit.alias :decigram, :decigrams
  unit.convert_to(:t) { |value| value / 10_000_000.0 }
  unit.convert_to(:kg) { |value| value / 10_000.0 }
  unit.convert_to(:hg) { |value| value / 1_000.0 }