Please research and propose the upgrade process similar to that of Wordpress. Then: - [x] Implement it for Engelsystem in a similar way - [x] Give the option in the UI to upgrade - [x] Show an icon "update" if updates are available - [x] in settings give the option "deactivate updates" and "automatic updates" - [ ] Write code tests - [x] Write a blog post about how Wordpress upgrades work and how you implemented it in the same way in Engelsystem. Include images and code info.