update README.md
diff --git a/README.md b/README.md
index eeaba2b..8e4365f 100644
--- a/README.md
+++ b/README.md
@@ -43,3 +43,5 @@
 ## Thanks
 
 * k-takata: base idea for IsCygwinTerminal
+
+    https://github.com/k-takata/go-iscygpty