articleModel.js

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

var Article = new Schema({
    title: String,
    content: String,
    created_at: {
        type: Date,
        default: Date.now
    },
    last_modified_at: {
        type: Date,
        default: Date.now
    }
});

module.exports = mongoose.model('Article', Article);