add link to GitHub Sponsor
diff --git a/readme.md b/readme.md
index 139ebca..edc9e5c 100644
--- a/readme.md
+++ b/readme.md
@@ -579,3 +579,5 @@
 ## Author
 MITSUNARI Shigeo(herumi@nifty.com)
 
+## Sponsors welcome
+[GitHub Sponsor](https://github.com/sponsors/herumi)