Change index.js to server.js
Change index.js to server.js

`npm start` defaults to run `node server.js`, which causes the previous example to fail because `index.js` was ignored.

This minor name change allows the example to be run properly.

See https://docs.npmjs.com/misc/scripts#default-values.
yous/new.nodejs.org,strawbrary/nodejs.org,phillipj/new.nodejs.org,phillipj/new.nodejs.org,marocchino/new.nodejs.org,abdelrahmansaeedhassan/yuri,abdelrahmansaeedhassan/yuri,nodejs/new.nodejs.org,matthewloring/new.nodejs.org,nodejs/new.nodejs.org,strawbrary/nodejs.org,matthewloring/new.nodejs.org,yous/new.nodejs.org,rnsloan/new.nodejs.org,marocchino/new.nodejs.org,rnsloan/new.nodejs.org