heirarhess.rb

module ProjectTypes
  def self.assignable_types
    ProjectTypes.constants.map{|klass|
      [ProjectTypes.const_get(klass)::ENGLISH_NAME, klass]
    }
  end
end

class ProjectTypes::TypeIII
  ENGLISH_NAME = 'Type III'
end

class ProjectTypes::TypeII
  ENGLISH_NAME = 'Type II'
end

puts ProjectTypes.available_types