update profile md

Author: JusterZhu

website/src/pages/Profile.md

@@ -21,6 +21,7 @@ hide_table_of_contents: true
 | Reddit: https://www.reddit.com/user/Cold_One188/             |
 | Product hunt: https://www.producthunt.com/@juster_zhu        |
 | Stackoverflow: https://stackoverflow.com/users/11280381/juster-zhu |
+| Mastodon: https://mastodon.social/@JusterZhu                 |