diff --git a/core/app/models/spree/promotion_rule.rb b/core/app/models/spree/promotion_rule.rb
index 2e5a17cc509..f40876a2035 100644
--- a/core/app/models/spree/promotion_rule.rb
+++ b/core/app/models/spree/promotion_rule.rb
@@ -5,7 +5,7 @@ class PromotionRule < ActiveRecord::Base
 
     scope :of_type, ->(t) { where(type: t) }
 
-    validate :promotion, presence: true
+    validates :promotion, presence: true
     validate :unique_per_promotion, on: :create
 
     def self.for(promotable)