How to add Redactor WYSIWYG to textarea?

Redactor is initialized https://imperavi.com/redactor/docs/get-started/initialization/ by adding class or id to textarea field. I tried using existing class, added css and js to /kirby/views/panel.php, but doesn’t work, I am getting:

cantfind

You would have to create a custom textarea field to make this work. You can’t just override the Vue-component like this, I think.