added code coverage

Author: matteoc99

README.md

@@ -7,6 +7,7 @@
 [![Latest Version on Packagist](https://img.shields.io/packagist/v/matteoc99/laravel-preference.svg?style=flat-square)](https://packagist.org/packages/matteoc99/laravel-preference)
 [![Total Downloads](https://img.shields.io/packagist/dt/matteoc99/laravel-preference.svg?style=flat-square)](https://packagist.org/packages/matteoc99/laravel-preference)
 [![Tests](https://github.com/matteoc99/laravel-preference/actions/workflows/tests.yml/badge.svg)](https://github.com/matteoc99/laravel-preference/actions/workflows/tests.yml)
+[![codecov](https://codecov.io/github/matteoc99/laravel-preference/graph/badge.svg?token=GS19E2ORR4)](https://codecov.io/github/matteoc99/laravel-preference)
 
 This Laravel package aims to store and manage user settings/preferences in a simple and scalable manner.