app/models/shipping_zone.rb
class ShippingZone < ApplicationRecord
has_many :shipping_methods
## if your model requires more shipping zones create a join table and delete state.shipping_zone_id
#has_many :state_shipping_zones
has_many :states#, :through => :state_shipping_zones
USA48 = 'USA'
ALASKA_HAWAII = 'Alaska and Hawaii'
CANADA = 'Canada'
USA_TERRITORY = 'USA Territory'
#OTHER_STATE = 'Other States'
LOCATIONS = [USA48, ALASKA_HAWAII, CANADA, USA_TERRITORY]#, OTHER_STATE]
validates :name, presence: true, length: { maximum: 255 }
accepts_nested_attributes_for :states
end