userModel2.js

var mongoose = require('mongoose');
var schema = new mongoose.Schema({

    name: {
        type: String,
        required: true,
        index: {unique: true}
    },

    banned: {
        type: Boolean,
        default: false
    }
});

// statics methods

schema.statics.findUserById = function(userId) {
    return Promise.resolve(this.findById(userId).exec());
}

schema.statics.findAllUsers = function() {
    return Promise.resolve(this.find({}).exec());
}

schema.statics.saveUser = function(user) {
    return Promise.resolve(this.save(user));
}

schema.statics.removeUserByName = function(name) {
    return Promise.resolve(this.findOneAndRemove({name: name}).exec());
}

// And so on..

var User = mongoose.model('User', schema);
module.exports = User;