models.js

var user = {
    username: { type: String, required: true },
    password: { type: String, required: true },
    
    valueOf: "username"
};

var tweet = {
    source: { type: String, default: "Web" },
    created_at: { type: Date, default: new Date() },
    text: { type: String, required: true },

    user: { type: String, required: true, foreignkey: "user" }
};