Fix vaulted duplicates method for older ruby versions (spree-contrib#266)

* fix Spree::Address.vaulted_duplicates method for older ruby versions

* add newline

Author: KacperMekarski

app/models/spree/address_decorator.rb

@@ -2,7 +2,7 @@ module Spree
   module AddressDecorator
     def self.prepended(base)
       base.scope :vaulted_duplicates, ->(address) do
-        where.not(id: address.id).
+        base.where.not(id: address.id).
           where.not(braintree_id: nil).
           where(address.attributes.except('id', 'updated_at', 'created_at', 'braintree_id', 'preferences'))
       end

spec/models/spree/address_spec.rb

@@ -0,0 +1,18 @@
+require 'spec_helper'
+
+describe Spree::Address do
+  describe '.vaulted_duplicates' do
+    subject { described_class.vaulted_duplicates(given_address) }
+
+    let(:given_address) { create(:address) }
+    let(:vaulted_duplicate) do
+      Spree::Address.create(given_address.attributes.symbolize_keys.except(:id, :updated_at, :created_at, :braintree_id, :preferences).
+                                                                    merge(braintree_id: rand(100)))
+    end
+    let(:some_address) { create(:address) }
+
+    it 'returns only vaulted duplicates of given address' do
+      expect(subject).to contain_exactly vaulted_duplicate
+    end
+  end
+end