Update README.md

Author: alyssaxuu

README.md

@@ -7,6 +7,8 @@ Mapus is a tool to explore and annotate collaboratively on a map. You can draw,
 
 <a href="https://www.producthunt.com/posts/mapus?utm_source=badge-top-post-badge&utm_medium=badge&utm_souce=badge-mapus" target="_blank"><img src="https://api.producthunt.com/widgets/embed-image/v1/top-post-badge.svg?post_id=307018&theme=light&period=weekly" alt="Mapus - An open source map tool with real-time collaboration | Product Hunt" style="width: 250px; height: 54px;" width="250" height="54" /></a>
 
+> You can support this project (and many others) through [GitHub Sponsors](https://github.com/sponsors/alyssaxuu)! ❤️
+
 Made by [Alyssa X](https://alyssax.com)
 
 ## Table of contents