Execute Many to Many migration using sequelize

Question

this is my first time using sequelize and I want to run a many to many migration. This is the setup of my models:

models/collection.js

'use strict';
module.exports = function(sequelize, DataTypes) {
  var Collection = sequelize.define('Collection', {
    title: DataTypes.STRING
  }, {
    classMethods: {
      associate: function(models) {
        // associations can be defined here
        Collection.belongsToMany(Post, { through: CollectionPost, foreignKey: 'collection_id' });
      }
    }
  });
  return Collection;
};

and models/post.js

'use strict';
module.exports = function(sequelize, DataTypes) {
  var Post = sequelize.define('Post', {
    title: DataTypes.STRING
  }, {
    classMethods: {
      associate: function(models) {
        // associations can be defined here
        Post.belongsToMany(Collection, { through: CollectionPost, foreignKey: 'post_id' });
      }
    }
  });

  return Post;
};

I understand that sequelize has sync method that syncs the models with migrations.However I want to sync only once and hence I wrote this small script to that:

const models = require('../models');

function test() {
    return models.sequelize.sync((err, response) => {
      console.log(err);
      console.log('.........');
      console.log(response);
    });
}
test();

However, this is not creating the CollectionPost table. What am I missing ?