FEATURE: new 'backup_frequency' site setting

app/jobs/scheduled/schedule_backup.rb

@@ -5,8 +5,14 @@ module Jobs
     sidekiq_options retry: false
 
     def execute(args)
-      return unless SiteSetting.backup_daily?
-      Jobs.enqueue_in(rand(10.minutes), :create_daily_backup)
+      return unless SiteSetting.backups_enabled?
+
+      if latest_backup = Backup.all[0]
+        date = Date.parse(latest_backup.filename[/\d{4}-\d{2}-\d{2}/])
+        return if date + SiteSetting.backup_frequency.days > Time.now
+      end
+
+      Jobs.enqueue_in(rand(10.minutes), :create_backup)
     end
   end
 end