Change /hello endpoint to use $fh.db to store string in MongoDB

hello.js

var $fh = require('fh-mbaas-api');

var options = {
    "act": "create",
    "type": "myFirstEntity",
    "fields": {
        "name": world
    }
};

$fh.db(options, function (err, data) {
    if (err) {
        console.error("Error " + err);
    } else {
        console.log(JSON.stringify(data));
    }
});

res.json({ msg: 'Hello ' + world });