Unable to track which user made changes for versioning using sequelize-paper-trail

I'm unable to track the user id even after passing usermodel in init options for sequelize-paper-trail. Below is model code:

var options = {
  User: 'user',
};
var PaperTrail = require('sequelize-paper-trail').init(sequelize, options);
PaperTrail.defineModels({});
module.exports = (sequelize, DataTypes) => {
  const Post = sequelize.define('post', {
    name: DataTypes.STRING
  }, {});
  Post.Revisions = Post.hasPaperTrail();
  Post.associate = function(models) {
    // associations can be defined here
  };
  return Post;
};

and in controller I have written like this:

post_update = await Post.update({name: "helllo world again"},{user_id: 1})