docs: add Discord community link

ZhiXiao-Lin · ZhiXiao-Lin · commit 4af95a473e2f · 2026-02-21T15:34:47.000+08:00
diff --git a/README.md b/README.md
@@ -113,6 +113,10 @@ let score = item.relevance_score_at(now, &config);
 cargo test
 ```
 
+## Community
+
+Join us on [Discord](https://discord.gg/XVg6Hu6H) for questions, discussions, and updates.
+
 ## License
 
 MIT
