Docs: Add "Badge" page

Closes #1750.

docs/_data/sitenav.yml

@@ -24,5 +24,7 @@
       href: /browser/#browser-support
     - name: About QUnit
       href: /about/
+    - name: Badge
+      href: /badge/
     - name: Brand Guidelines
       href: /brand/

docs/badge.md

@@ -0,0 +1,20 @@
+---
+layout: page
+title: Tested with QUnit Badge
+---
+
+<p class="lead">Use the following markup to embed a "Tested with QUnit" badge in your documentation.</p>
+
+[![Tested with QUnit](./testedwith.svg)](/)
+
+Copy the Markdown snippet, and e.g. paste above the title your README.
+
+```md
+[![Tested with QUnit](https://qunitjs.com/testedwith.svg)](https://qunitjs.com/)
+```
+
+HTML version:
+
+```html
+<a href="https://qunitjs.com/"><img src="https://qunitjs.com/testedwith.svg" alt="Tested with QUnit"></a>
+```

docs/brand.md

@@ -83,3 +83,7 @@ You can browse the [2013 version of the website](https://web.archive.org/web/201
 In 2018, Trent Willis [designed](https://github.com/qunitjs/qunitjs.com/issues/151#issuecomment-655154878) a new homepage for QUnit. In 2020, Timo Tijhof [launched](https://github.com/qunitjs/qunit/issues/1458#issuecomment-661576550) the redesign with a matching redesign of the API documentation. The QUnit site framework is published as [jekyll-theme-amethyst](https://github.com/qunitjs/jekyll-theme-amethyst).
 
 ![](/img/2020-website-qunit.png)
+
+## Tested with QUnit Badge
+
+Refer to [Badge](./badge.md) for markup to embed in your README.