diff --git a/app/models/puzzle.rb b/app/models/puzzle.rb
index 216b7ca..5734d14 100644
--- a/app/models/puzzle.rb
+++ b/app/models/puzzle.rb
@@ -21,7 +21,7 @@
 class Puzzle < ApplicationRecord
   belongs_to :contest
 
-  has_many :completions
+  has_many :completions, dependent: :destroy
   has_one_attached :image
 
   validates :name, presence: true