Make distributor payment method multi-select

app/models/spree/payment_method_decorator.rb

@@ -3,18 +3,15 @@ Spree::PaymentMethod.class_eval do
 
   belongs_to :distributor, :class_name => 'Enterprise'
 
-  validates_presence_of :distributor_id
-
-  attr_accessible :distributor_id
+  attr_accessible :distributor_ids
 
   # -- Scopes
-  scope :in_distributor, lambda { |distributor| where(:distributor_id => distributor) }
-
   scope :managed_by, lambda { |user|
     if user.has_spree_role?('admin')
       scoped
     else
-      where('distributor_id IN (?)', user.enterprises)
+      joins(:distributors).
+      where('distributors_payment_methods.distributor_id IN (?)', user.enterprises)
     end
   }
 

app/overrides/spree/admin/payment_methods/_form/add_distributor_to_admin_payment_method_edit.html.haml.deface

@@ -1,9 +0,0 @@
-/
-  insert_before '[data-hook="environment"]'
-
-= f.field_container :distributor do
-  = f.label :distributor
-  %br
-
-  = collection_select(:payment_method, :distributor_id, Enterprise.is_distributor.managed_by(spree_current_user), :id, :name, {:include_blank => false}, {:class => "select2 fullwidth"})
-  = f.error_message_on :distributor

app/overrides/spree/admin/payment_methods/_form/add_distributors.html.haml.deface

@@ -0,0 +1,9 @@
+/
+  insert_before '[data-hook="environment"]'
+
+= f.field_container :distributors do
+  = f.label :distributors
+  %br
+  - distributors = Enterprise.is_distributor.managed_by(spree_current_user) | f.object.distributors
+  = collection_select(:payment_method, :distributor_ids, distributors, :id, :name, {include_blank: false}, {class: "select2 fullwidth", multiple: true})
+  = f.error_message_on :distributors