Limiting the nestable levels?

[AmitJoki]

If I want to limit the nestable levels to upto 2, how can I do it? Is there any options for it?
Also, I'd like to ask if installing this gem is a overkill if all I want is two-level nesting?

[sximba]

Firstly, yes I think this gem is overkill if all you want is two level nesting. The nested set model is awesome for large and complex nested sets but it is expensive to update (when you add a comment and move it to child, it updates the entire table).

It doesn't have an option to limit the nesting. You could modify it though to achieve that.