Issues with migration

When I try to add a column in the existing table getting an error.

PHP Code:

<?php namespace App\Database\Migrations;

use CodeIgniter\Database\Migration;

class AddColumnCreatedAt extends Migration
{
    public function up()
    {
        $this->forge->addColumn('users', 'created_at');
    }

    //--------------------------------------------------------------------

    public function down()
    {
        $this->forge->dropColumn('users', 'created_at');
    }
}

This is what i am doing

Getting error

Running all new migrations... 


PHP Code:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 2 


PHP Code:

/var/www/html/appstart/vendor/codeigniter4/framework/system/Database/MySQLi/Connection.php - 330 


Best,

You forget to fill in what datatype 'create_at' is.
Example from the documentation.

PHP Code:

$fields = [
        'created_at' => ['type' => 'DATETIME']
];
$forge->addColumn('users', $fields);
// Executes: ALTER TABLE users ADD preferences DATETIME 


But can also use the model for filling the 'created at' field.

PHP Code:

<?php namespace App\Models;

use CodeIgniter\Model;

class UserModel extends Model
{
        protected $table      = 'users';
        protected $primaryKey = 'id';

        protected $returnType = 'array';
        protected $useSoftDeletes = true;

        protected $allowedFields = ['name', 'email'];

        protected $useTimestamps = true;
        protected $createdField  = 'created_at';
        protected $updatedField  = 'updated_at';
        protected $deletedField  = 'deleted_at';

        protected $validationRules    = [];
        protected $validationMessages = [];
        protected $skipValidation     = false;
} 


Be sure you have added these field to your database.

André