Best way for user to create category tree

Our clients need to create a shop structure with many categories and subcategories, and our current system is not very easy for them.

I thought the best way would be just a blank text area - creating categories by writing it's name and pressing enter, and subcategories by pressing tab and writing name.

It's probably the quickest, but on the other hand, I think it might not be obvious enough and also you can't set up other attributes of the category.

What would be the best practice to enable users to quickly create a whole set of categories?