Added bundled theming example (#82)

Author: JonShort

README.md

@@ -349,7 +349,13 @@ The `defaultProps` you'd typically apply in a basic use-case, contain a default
 This theme is [duotoneDark](./src/themes/duotoneDark.js).
 
 While all `className`s are provided with `<Highlight />`, so that you could use your good
-old Prism CSS-file themes, you can also choose to use `react-prism-renderer`'s themes.
+old Prism CSS-file themes, you can also choose to use `react-prism-renderer`'s themes like so:
+
+```jsx
+import dracula from 'prism-react-renderer/themes/dracula';
+
+<Highlight theme={dracula} {/* ... */} />
+```
 
 These themes are JSON-based and are heavily inspired by VSCode's theme format.