Measurement.define(:'tsp.') do |unit|
  unit.alias :tsp, :teaspoon, :teaspoons
  unit.convert_to(:gal) { |value| value / 768.0 }
  unit.convert_to(:qt) { |value| value / 192.0 }
  unit.convert_to(:pt) { |value| value / 96.0 }