Link to documentation and badge

README.md

@@ -4,12 +4,15 @@
 [![OCaml Version](https://img.shields.io/badge/OCaml-4.14_--_5.x-blue?logo=ocaml&logoColor=white)](https://github.com/codex-semantics-library/patricia-tree/blob/main/dune-project)
 [![GitHub License](https://img.shields.io/github/license/codex-semantics-library/patricia-tree)](https://github.com/codex-semantics-library/patricia-tree/blob/main/LICENSE)
 [![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/codex-semantics-library/patricia-tree/ocaml.yml)](https://github.com/codex-semantics-library/patricia-tree/actions/workflows/ocaml.yml)
-
+[![Documentation](https://img.shields.io/website?url=https%3A%2F%2Fcodex.top%2Fpatricia-tree%2F&up_message=online&down_message=offline&label=documentation)](https://codex.top/patricia-tree/)
 
 This is an [OCaml](https://ocaml.org/) library that implements sets and maps as
 Patricia Trees, as described in Okasaki and Gill's 1998 paper [*Fast mergeable integer maps*](https://www.semanticscholar.org/paper/Fast-Mergeable-Integer-Maps-Okasaki-Gill/23003be706e5f586f23dd7fa5b2a410cc91b659d).
 It is a space-efficient prefix trie over the big-endian representation of the key's integer identifier.
 
+The documentation for this library can be found online at
+[codex.top/patricia-tree/](https://codex.top/patricia-tree/).
+
 **Table of Contents:**
 <!-- TOC -->
 - [Installation](#installation)