Column sorting for Laravel 5.5-8 and above

This repository is a fork of the Laravel Column Sorter originally created by https://github.com/Kyslik/column-sortable.

I have modified the code so now it works for up to 4 levels of nesting such as ->sortable(['relation1.subrelation2.subrelation3.subrelation4.columnName' => 'desc'])

Please raise an issue if you find any bug or want to improve. Thank you