[Spree 2 Upgrade] undefined method zone_id for ShippingMethod

[sauloperez]

Description

While trying to create a shipping method from /admin I got the following error in the Rails server:

Completed 500 Internal Server Error in 442.9ms (ActiveRecord: 5.7ms)
** [Bugsnag] No API key configured, couldn't notify

ActionView::Template::Error (undefined method `zone_id' for #<Spree::ShippingMethod:0x00562b39694b40>):
    26:       <%= f.label :zone_id, t(:zone) %>
    27:     </div>
    28:     <div class="omega eight columns">
    29:       <%= f.collection_select(:zone_id, @available_zones, :id, :name, {}, {:class => 'select2 fullwidth'}) %>
    30:       <%= error_message_on :shipping_method, :zone_id %>
    31:     </div>
    32:   </div>
  lib/spree/core/controller_helpers/respond_with_decorator.rb:15:in `call'
  lib/spree/core/controller_helpers/respond_with_decorator.rb:15:in `respond_with'

It seems like the zone_id column was moved out of the spree_shipping_methods table.

Expected Behavior

Shipping methods can be created from /admin. This deserves some initial investigation which might change the scope of this issue. It could be harder than a simple one-PR fix.

Actual Behavior

The app displays the error showed above.

Steps to Reproduce

Visit /admin/shipping_methods/new.

[luisramos0]

To get the top level epic cleaner, I moved this one under the epic #2011 Multi Shipments. This is in the backoffice but the work is closely related to the shipments work that needs to be done.

[luisramos0]

I just realized #2744 is an exact duplicate of this issue. My mistake, didnt see the duplication. Closing this one as 2744 has now more info and context.