```ruby
module Xeroid
  module Serialisers
    autoload :Invoice, 'xeroid/serialisers/invoice'
  end
end
```

Add the Payment serialiser to the Serialiser autoloaded-modules
user
```ruby
module Xeroid
  module Serialisers
    autoload :Invoice, 'xeroid/serialisers/invoice'
    autoload :Payment, 'xeroid/serialisers/payment'
  end
end
```
assistant