Update README.md

Author: pose

README.md

@@ -1,3 +1,28 @@
 ##JWT.io
 
 [![Build Status](https://travis-ci.org/jsonwebtoken/jsonwebtoken.github.io.png?branch=master)](https://travis-ci.org/jsonwebtoken/jsonwebtoken.github.io)
+
+### How to build
+
+> Warning: `index.html` in the root folder is a generated file please edit `html/index.html`.
+
+First, install the required dependencies:
+
+```sh
+npm install && bower install
+```
+
+In order to build (and run) the project execute:
+
+```sh
+grunt
+```
+
+And then go to http://0.0.0.0:8000.
+
+That will create the css from the less files, minify the javascript and generate `index.html` from `html/index.html`. 
+
+
+### Happy hacking!
+
+