class SetDefaultStockLocationOnShipments < ActiveRecord::Migration
  def up
    if Spree::Shipment.where('stock_location_id IS NULL').count > 0
      location = DefaultStockLocation.find_or_create
      Spree::Shipment.where('stock_location_id IS NULL').update_all(stock_location_id: location.id)
    end
  end
end

Add migration to set default stock location on all shipments without stock location
Add migration to set default stock location on all shipments without stock location

This is a modified version of this spree migration: https://github.com/spree/spree/commit/219e09b
