add GitHub Pages badge to README

Author: levno-710

README.md

@@ -8,6 +8,9 @@
 
 <br/>
 
+<a href="https://prometheus-lua.github.io/Prometheus/">
+  <img src="https://img.shields.io/badge/Prometheus%20Web-Open-0F766E?style=for-the-badge&logo=github&logoColor=white" alt="Open Prometheus Web UI" />
+</a>
 <a href="https://github.com/prometheus-lua/Prometheus/actions/workflows/Test.yml">
   <img src="https://img.shields.io/github/actions/workflow/status/prometheus-lua/Prometheus/Test.yml?branch=master&style=for-the-badge&label=Tests" alt="Tests" />
 </a>
@@ -46,6 +49,14 @@ Currently, Prometheus supports:
 
 ## Quick Start
 
+Try the browser version first:
+
+
+<a href="https://prometheus-lua.github.io/Prometheus/">
+  <img src="https://img.shields.io/badge/Prometheus%20Web-Open-0F766E?style=for-the-badge&logo=github&logoColor=white" alt="Open Prometheus Web UI" />
+</a>
+
+### Local CLI usage
 Clone the repository:
 
 ```bash