diff --git a/app/models/project_trend.rb b/app/models/project_trend.rb
index 7642e1dfb..bc9dd2712 100644
--- a/app/models/project_trend.rb
+++ b/app/models/project_trend.rb
@@ -22,7 +22,7 @@ class ProjectTrend < ApplicationRecord
   CREATE = 'create'
   MERGE = 'merge'
   
-  belongs_to :project
+  belongs_to :project, optional: true
   belongs_to :trend, polymorphic: true, optional: true
   belongs_to :user
 end