jobs: migrate pool category updates to ActiveJob.

app/jobs/update_pool_pseudo_tags_job.rb

@@ -0,0 +1,8 @@
+class UpdatePoolPseudoTagsJob < ApplicationJob
+  queue_as :default
+  queue_with_priority 20
+
+  def perform(pool)
+    pool.update_category_pseudo_tags_for_posts
+  end
+end