sequelize migrations, make sure you handle the promises correctly!

sequelize-promise-migration.js

"use strict";

module.exports = {
  up: function(queryInterface, Sequelize) {
    //
    // queryInterface methods DO return promises. Either of the following with work
    //
    // return queryInterface.addColumn(...)
    // .then(() => queryInterface.doSomething(...)) 
    // etc.
    // ... or this:
    return Promise.resolve()
      .then(() => queryInterface.addColumn("foo", "id", {
          type: Sequelize.INTEGER,
          autoIncrement: true,
        })
      )
      .then(() => queryInterface.removeConstraint("foo", "foo_pkey"))
      .then(() => queryInterface.addConstraint("foo", ["id", "fooId"], {
          type: "primary key",
          name: "foo_pkey",
        })
      )
      .then(() => {
        // this will also work
        // multi line function
        // ...doing work
      })
      .then(/* this notation will not wait for execution of function */)
      .then(() => /* but this notation will :) */);
  },

  down: function(queryInterface, Sequelize) {
    queryInterface.sequelize.query();
  },
};