Feature/docs (#67)

website/content/docs/custom-icons.mdx

@@ -0,0 +1,27 @@
+---
+group: Customization
+title: Adding Custom Icons
+weight: 100
+---
+
+The Static CMS exposes a `window.CMS` global object that you can use to register custom icons via `registerIcon`. The same object is also the default export if you import Static CMS as an npm module.
+
+Custom icons can be used with [Collections](/docs/collection-overview) or [Custom Links & Pages](/docs/additional-links)
+
+## Params
+
+| Param | Type                                                                           | Description                                        |
+| ----- | ------------------------------------------------------------------------------ | -------------------------------------------------- |
+| name  | string                                                                         | A unique name for the icon                         |
+| name  | [React Function Component](https://reactjs.org/docs/components-and-props.html) | A React functional component that renders the icon |
+
+## Example
+
+This example uses Font Awesome to supply the icon.
+
+```js
+import { faHouse } from '@fortawesome/free-solid-svg-icons';
+import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
+
+cmsApp.registerIcon('house', <FontAwesomeIcon icon={faHouse} size="lg" />);
+```