Extending Solidus to have file upload attached to an order

app/models/upload/graphic.rb

class Upload::Graphic < ApplicationRecord
  belongs_to :order, class_name: "Spree::Order", optional: true
  has_one_attached :image

  def order
    Spree::Order.find(spree_order_id)
  end
end

migration

class CreateUploadGraphics < ActiveRecord::Migration[6.1]
  def change
    create_table :upload_graphics do |t|
      t.references :spree_order, foreign_key: true
      t.timestamps
    end
  end
end

This part works great i can do .order on an Upload::Graphic object and it returns the order.

Question: how do i do the inverse? Start with a Spree::Order and find the Upload::Graphic