chore: add discord link

README.md

@@ -1,6 +1,7 @@
 [![Test Status](https://github.com/monkeyWie/gopeed/workflows/test/badge.svg)](https://github.com/monkeyWie/gopeed/actions?query=workflow%3Atest)
 [![Codecov](https://codecov.io/gh/monkeyWie/gopeed/branch/main/graph/badge.svg)](https://codecov.io/gh/monkeyWie/gopeed)
 [![Release](https://img.shields.io/github/release/monkeyWie/gopeed.svg?style=flat-square)](https://github.com/monkeyWie/gopeed/releases)
+[![Discord](https://img.shields.io/discord/1037992631881449472?label=Discord&logo=discord&style=social)](https://discord.gg/ZUJqJrwCGB)
 
 ![](_docs/img/banner.png)