Sequelize 4.3.2 n:m (many-to-many) association: Unhandled rejection SequelizeEagerLoadingError

Question

I have 3 models: User, Project, UserProject:

module.exports = function (sequelize, DataTypes) {
  var User = sequelize.define('User', {
  title: DataTypes.STRING,
  description: DataTypes.STRING
}, {
  classMethods: {
    associate: function (models) {
      User.belongsToMany(models.Project, { 
        through: 'UserProject',
        foreignKey: 'userId'
      })
    }
  },
  freezeTableName: true
})
  return User
}


module.exports = function (sequelize, DataTypes) {
  var Project = sequelize.define('Project', {
  title: DataTypes.STRING,
  description: DataTypes.STRING
  }, {
  classMethods: {
    associate: function (models) {
      Project.belongsToMany(models.User, { 
        through: 'UserProject',
        foreignKey: 'projectId'
      })
    }
  },
  freezeTableName: true
})
  return Project
}


module.exports = function (sequelize, DataTypes) {
 var UserProject = sequelize.define('UserProject', {
  userId: DataTypes.INTEGER,
  projectId: DataTypes.INTEGER,
 }, {
  classMethods: {
 },
  freezeTableName: true
 })
  return UserProject
}

The code above worked perfectly with some old version of Sequelize. Now I updated to Sequelize 4.3.2 and I get the following error when trying to use these models:

Unhandled rejection SequelizeEagerLoadingError: Project is not associated to User!

What is wrong with this? I'm trying to do many-to-many association here, and get Users included when findAll Projects and vice versa. I'm using MySQL as a database.

Here is the findAll-part:

function getUsersWithProjects (request, response, next) {
  models.User.findAll({
    include: [{
      model: models.Project,
    }]
  });
}

Answer 1

Now I found the solution. Apparently they have removed classMethods and instanceMethods, so associations is now defined like this:

module.exports = function (sequelize, DataTypes) {
  var User = sequelize.define('User', {
    title: DataTypes.STRING,
    description: DataTypes.STRING
  }, {
   freezeTableName: true
  })
  User.associate = function (models) {
   User.belongsToMany(models.Project, { 
    through: 'UserProject',
    foreignKey: 'userId'
   })
 };
 return User
}

Source: http://docs.sequelizejs.com/manual/tutorial/upgrade-to-v4.html