That's a sample application to demonstrate working with Ethereum from js using web3.js and ethereumjs-tx.
Set your sandboxId in web/src/app.js. You can find id of your running sandbox on the sandbox panel.
Building:
$ npm install gulp-cli -g
$ npm install
$ gulp
Testing:
$ gulp test
Running:
$ cd web
$ npm install http-server -g
$ http-server