How to make a multi-level referral system using SequelizeJs?

Question

PostgreSQL

Hello, how can I implement a multi-level referral system using SequelizeJs?
Now I have a single-level one, in the table with the user there is a ref field, and a link has been added. Thus, I can get a user and a referral, but I can no longer get a referral of a referral.

const users = sequelize.define('users', {
  login:  { 
    type: Sequelize.STRING, 
    allowNull: false,
    unique: true
  },
  password: { 
    type: Sequelize.STRING, 
    allowNull: false
  },
  ref: { 
    type: Sequelize.INTEGER ,
    allowNull: true,
    foreignKey : true
  }
})

users.hasMany(users, {foreignKey: 'ref', as: 'userRefList'})
users.belongsTo(users, {foreignKey : 'ref', as: 'userRef'})

Is it possible to get the whole chain of referrals in such an implementation?
Or suggest another, more convenient and correct way.
Thank you!