Update README for NPM publish

README.md

@@ -2,7 +2,31 @@
 
 Free SVG icons for popular brands, started by [Dan Leech](https://twitter.com/bathtype). [See them all on one page at **simpleicons.org**](https://simpleicons.org). Contributions, corrections & requests can be made on GitHub.
 
-## To do
+## Usage
 
-- [ ] Analytics tracking for icon clicks
-- [ ] New README.md
+Icons can be downloaded as SVGs directly from [our website](https://simpleicons.org/) - simply click the icon you want, and the download should start automatically.
+
+### Node Usage
+
+The icons are also available through our npm package. To install, simply run:
+
+```
+$ npm install simple-icons
+```
+
+The API can then be used as follows:
+
+```
+const simpleIcons = require('simple-icons');
+
+console.log(simpleIcons['Google+']);
+
+/*
+{
+    title: 'Google+',
+    hex: 'DC4E41',
+    source: 'https://developers.google.com/+/branding-guidelines',
+    svg: '<svg aria-labelledby="simpleicons-googleplus-icon" role="img" viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">...</svg>'
+}
+*/
+```