在节点中创建猫鼬模型的新实例-将第一项添加到一个嵌入式数组中

这是我当前的代码：

假设我有以下猫鼬模型：

// This is the car model.

var mongoose = require('mongoose');
var ObjectId = mongoose.Schema.Types.ObjectId;
var Schema = mongoose.Schema;

//  Setup a mongoose model, and pass it to module.exports.

module.exports = mongoose.model('Car', new Schema({
    manufacturer: String,
    model: String,
    owners: [{type: ObjectId, ref: 'Owner'}]
}));

我想在我的REST api中使用它，如下所示-在这段代码中，我实质上是在尝试创建car对象的实例，然后将当前的所有者ID传入，成为该数组的第一项。 “所有者列表”

app.post('/cars/create', function(req,res){

    if( req.body.manufacturer && req.body.model && req.body.ownerId)
    {
        newCar = new Car(
            manufacturer: req.body.manufacturer,
            model: req.body.model,
            owners: // NOT SURE WHAT TO DO HERE 
        });
    }
});