jobs: add ability to search jobs on /jobs page.

Add ability to search jobs on the /jobs page by job type or by status.

Fixes #2577 (Search filters for delayed jobs). This wasn't possible
before with DelayedJobs because it stored the job data in a YAML string,
which made it difficult to search jobs by type. GoodJobs stores job data
in a JSON object, which is easier to search in Postgres.

app/models/background_job.rb

@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+# A BackgroundJob is a job in the good_jobs table. This class is simply an
+# extension of GoodJob::ActiveJobJob, with a few extra methods for searching jobs.
+#
+# @see https://github.com/bensheldon/good_job/blob/main/lib/good_job/active_job_job.rb
+class BackgroundJob < GoodJob::ActiveJobJob
+  concerning :SearchMethods do
+    class_methods do
+      def default_order
+        order(created_at: :desc)
+      end
+
+      def status_matches(status)
+        case status.downcase
+        when "queued"
+          queued
+        when "running"
+          running
+        when "finished"
+          finished
+        when "discarded"
+          discarded
+        else
+          all
+        end
+      end
+
+      def name_matches(name)
+        class_name = name.tr(" ", "_").camelize + "Job"
+        where_json_contains(:serialized_params, { job_class: class_name })
+      end
+
+      def search(params)
+        q = search_attributes(params, :id, :created_at, :updated_at, :queue_name, :priority, :serialized_params, :scheduled_at, :performed_at, :finished_at, :error, :active_job_id, :concurrency_key, :cron_key, :retried_good_job_id, :cron_at)
+
+        if params[:name].present?
+          q = q.name_matches(params[:name])
+        end
+
+        if params[:status].present?
+          q = q.status_matches(params[:status])
+        end
+
+        q.apply_default_order(params)
+      end
+    end
+  end
+end