docs: Add npm install instructions

Cole Bemis · web-flow · commit f72c5dd2152d · 2017-08-01T12:18:57.000-07:00
diff --git a/README.md b/README.md
@@ -9,7 +9,11 @@
 
 Feather is a collection of **simply beautiful open source icons**. Each icon is designed on a 24x24 grid with an emphasis on simplicity, consistency and readability.
 
-[feathericons.com](https://feathericons.com)
+**[feathericons.com](https://feathericons.com)**
+
+```
+npm install feather-icons
+```
 
 ## Table of Contents
 
