docs: add github page link to README

Author: Lee-W

docs/README.md

@@ -9,6 +9,8 @@ versions](https://img.shields.io/pypi/pyversions/commitizen.svg?style=flat-squar
 
 ![Using commitizen cli](images/demo.gif)
 
+View full [documentation](https://commitizen-tools.github.io/commitizen/).
+
 ## About
 
 Commitizen is a tool designed for teams.