Using GlobalID for custom classes (to pass into Rails ActiveJob)

global-id-custom.rb

```
class Currency
  include GlobalID::Identification
  attr_accessor :a, :b
  
  def initialize(a, b)
    @a = BigDecimal(a.to_f, 2)
    @b = b.to_s
  end
  
  def id
    "#{a}--#{b}"
  end
  
  def self.find(id)
    new(*id.split('--', 2))
  end
end

money = Currency.new(10, 'USD')
# => #<Currency:0x00007fe220581bf0 @a=10, @b="USD"> 

gid = GlobalID.create(money)
# => #<GlobalID:0x00007fe216c2e778 @uri=#<URI::GID gid://my_app/Currency/10.0--USD>> 

money_in_active_job = GlobalID.find(gid)
# => #<Currency:0x00007fe21f65bb30 @a=10, @b="USD">
```