Add scheduled statuses (#9706)

Fix #340

app/workers/scheduler/scheduled_statuses_scheduler.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+class Scheduler::ScheduledStatusesScheduler
+  include Sidekiq::Worker
+
+  sidekiq_options unique: :until_executed, retry: 0
+
+  def perform
+    due_statuses.find_each do |scheduled_status|
+      PublishScheduledStatusWorker.perform_at(scheduled_status.scheduled_at)
+    end
+  end
+
+  private
+
+  def due_statuses
+    ScheduledStatus.where('scheduled_at <= ?', Time.now.utc + PostStatusService::MIN_SCHEDULE_OFFSET)
+  end
+end