Quero adicionar os dois IDs( req.body.meuId e req.body.outroId ) dentro do array matchs dentro do field "campo"

controller.js

update_match = function(req,res){
    var query = { _id : req.params.id }
      , mod = { $pushAll : { 'matchs.campo' : [mongoose.Types.ObjectId( req.body.meuId ),
                                    mongoose.Types.ObjectId( req.body.outroId )] } }
      ;

    Model.update( query, mod, function(err,data){
        if (err){ console.log( err ); return res.json(err); }

        console.log( 'Sucesso: ' + data );
        res.json( data );
    })
};

registro.js

{
  "_id": ObjectId("54ce4a92dba7d25e10a30cd0"),
  "users": [
    ObjectId("54cd3f34a5e4e1c4d181fcd5"),
    ObjectId("54ce4aa1dba7d25e10a30cd1")
  ],
  "matchs": [ ],
  "name": "Nome do Evento",
  "idFace": "456875432",
  "__v": 0
}

schema.js

(function(){
	'use_strick'

	var mongoose = require('mongoose');

	var Schema = mongoose.Schema;

	var EventoSchema = new Schema({
	    idFace : { type : String, default : '' }
	  , name : { type : String, default : '' }
	  , matchs : [{ type : Schema.Types.ObjectId, ref : 'User' }] 
	  , users : [{ type : Schema.Types.ObjectId, ref: 'User' }]
	});

	module.exports = mongoose.model( 'Evento', EventoSchema );

})();