diff --git a/Makefile b/Makefile
index 30ddf7e..c83c9fa 100644
--- a/Makefile
+++ b/Makefile
@@ -9,7 +9,7 @@ docs-serve: docs/index.md
 docs-build: docs/index.md
 	docfx docs/docfx.json
 
-docs/index.md: 
+docs/index.md: README.md
 	cp README.md docs/index.md
 
 lint: