How to exports method in node orm with express?

I have two files:

api.js this is a router file

q.js this file have database connection and some operate with model

I want exports some method from q.js to api.js

The code like this:

api.js

var express = require('express');
var q = require('./q.js');

var router = express.Router();

router.get('/users', q.getAllUsers(res, req));

module.exports = router;

q.js

var orm = require('orm');
var db = orm.connect(...);
var q = {};

db.on('connect', function(err, db){
    db.load('./models', function(){
        var User = db.model.User;
        q.getAllUsers = function(res, req){
           //do some query and return the result...
        }
    })
})

module.exprots = q;

Because database connect is Asynchrony， so q in api.js is empty.

How could I do this correct？

Thanks a lot