async_mongo.js

var async = require('async'),
    mongoose = require('mongoose'),
    Review = require('../models/review'),
    config = require('../tools/config');

async.series([
    function(callback){
        mongoose.connect(config.DB_URL, callback)
    },
    function(callback){
        var t = new Review({
            name: 'testing'
        });
        t.save(function(err){
            if(!err){
                console.log('added');
            }
        });
        callback();
    },
    function(callback){
        mongoose.disconnect(callback);
    }
], function(err, res){
    if(!err){
        console.log('all done')
    }
});