Update README.md

Author: woensug-choi

README.md

@@ -3,4 +3,6 @@
 [![Publish a Docker image (AMD64; Common X86_64 Linux Machine)](https://github.com/IOES-Lab/dave/actions/workflows/docker-amd64.yml/badge.svg)](https://github.com/IOES-Lab/dave/actions/workflows/docker-amd64.yml)
 [![Publish a Docker image (ARM64; Apple Silicon)](https://github.com/IOES-Lab/dave/actions/workflows/docker-arm64v8.yml/badge.svg?branch=ros2)](https://github.com/IOES-Lab/dave/actions/workflows/docker-arm64v8.yml)
 
+Documentation is currently at [http://dave-ros2.notion.site](http://dave-ros2.notion.site)
+
 For contribution, do `pip3 install pre-commit && pre-commit install && pre-commit run --all-files` before commit.