Sequelize migration converting Sequelize.UUID primary key field to integer autoincrement in MYSQL - migration

Question

I am using sequelize CLI to generate and run db migrations. The issue I am having is the id field set to data type Sequelize.UUID appearing as an autoincrement integer in mysql. Here is my user model and migration:
User Model
'use strict';
module.exports = (sequelize, DataTypes) => {
const User = sequelize.define('User', {
UserName: {type:DataTypes.STRING,unique:true,allowNull:false},
FirstName:{type: DataTypes.STRING,allowNull:true},
LastName: {type:DataTypes.STRING,allowNull:true},
Email: {type:DataTypes.STRING,allowNull:false,unique:true,validate: { isEmail: {msg: "Invalid Email"} }},
Password: {type:DataTypes.STRING,allowNull:false},
Avatar: {type:DataTypes.STRING,allowNull:true},
}, {});
User.associate = function(models) {
User.hasMany(models.RoleUser,
{
foreignKey:'UserId',
as:'userroles',
sourceKey:'id'
}),
User.belongsTo(models.Country,
{
foreignKey:'CountryId',
targetKey:'id'
}),
User.belongsToMany(models.Role,
{
through: 'RoleUser',
foreignkey:'UserId'
})
};
return User;
};
**User Migration file:**
'use strict';
const uuidv4 = require('uuid/v4');
module.exports = {
up: (queryInterface, Sequelize) => {
return queryInterface.createTable('Users', {
id: {
allowNull: false,
primaryKey: true,
type: Sequelize.UUID
defaultValue:uuidv4()
},
UserName: {
type: Sequelize.STRING
},
FirstName: {
type: Sequelize.STRING
},
LastName: {
type: Sequelize.STRING
},
Email: {
type: Sequelize.STRING
},
Password: {
type: Sequelize.STRING
},
Avatar: {
type: Sequelize.STRING
},
createdAt: {
allowNull: false,
type: Sequelize.DATE
},
updatedAt: {
allowNull: false,
type: Sequelize.DATE
}
});
},
down: (queryInterface, Sequelize) => {
return queryInterface.dropTable('Users');
}
};
AFTER MIGRATION, THE HIS FIELD IS CONVERTED TO INT AUTOINCREMENT IN MYSQL:
id: {
allowNull: false,
primaryKey: true,
type: Sequelize.UUID
defaultValue:uuidv4()
},
Any pointer as to why this is happening? Please assist. Even the associations seem not to be formed at all as foreign keys are of type Sequelize.UUID

Answer 1

I fixed the problem by adding the id field on model with primary key property set to true.
id: {
type:DataTypes.UUID,
allowNull:false,
unique:true,
primaryKey:true
},
Its like sequelize will automatically generate id field of type INTEGER AUTOINCREAMENT if the model does not have a field with primary key set to true.