add more docs

Author: christian-bromann

CONTRIBUTING.md

@@ -1,6 +1,6 @@
-# Contributing to docusaurus-theme-github-codeblock
+# Contributing to `docusaurus-theme-github-codeblock`
 
-**Thank you for your interest in docusaurus-theme-github-codeblock. Your contributions are highly welcome.**
+**Thank you for your interest in `docusaurus-theme-github-codeblock`. Your contributions are highly welcome.**
 
 There are multiple ways of getting involved:
 

README.md

@@ -15,6 +15,16 @@ npm install @saucelabs/theme-github-codeblock
 
 ## Usage
 
+Add the theme plugin to your list of themes in the `docusaurus.config.js`:
+
+```js
+    // ...
+    themes: [
+        '@saucelabs/theme-github-codeblock'
+    ],
+    // ...
+```
+
 In order to reference GitHub snippets in your markdown, create code blocks with a `reference` attached to the language meta string and put the link to your GitHub reference in the code block, e.g.:
 
     ```js reference