controller.js

var usuarioJaExiste = function ( err, data, res, req ) {
    var dados,
        model;
    
    if ( err ) return res.json(err);
    if ( data ) return res.json({ Error: "Usuario ja existe.", Code: 0 });
            
    dados = {
        idFace: req.body.idFace,
        arrayUsuario: [{
            name : req.body.name,
            gender: req.body.gender
        }]
    }
    
    model = new Model( dados );
    
    model.save( function(err, data){
        callback( err, data, res );
    });
};

model.js

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

var UsuarioSchema = new Schema({
    arrayUsuario: [{
        name : { type: String, default: '' }
      , age: { type: String, default: '' }
      , gender: { type: String, default: '' }
      , idEventos: { type: Array, default: [] }
      , matchs: { type: Array, default: [] }
      , fotos: { type: Array, default: [] }
    }]
  , idFace: { type: String, required: true, unique: true }
  , created_at: { type: Date, default: Date.now }
});

module.exports = mongoose.model( 'Usuario', UsuarioSchema );