fix for multi-used relations

spec/jobs/domain/fa/job/favs_job_spec.rb

@@ -298,7 +298,13 @@ describe Domain::Fa::Job::FavsJob do
       end
 
       it "creates new FA post models and enqueues scans" do
-        p1 = Domain::Post::FaPost.create!(fa_id: fa_ids[0], creator: user)
+        p1 =
+          Domain::Post::FaPost
+            .create!(fa_id: fa_ids[0])
+            .tap do |p|
+              p.creator = user
+              p.save!
+            end
         expect do perform_now(args) end.to change(
           Domain::Post::FaPost,
           :count,