app_cfg_migration.php

<?php defined('BASEPATH') OR exit('No direct script access allowed');
/*
|--------------------------------------------------------------------------
| Enable/Disable Migrations
|--------------------------------------------------------------------------
|
| Migrations are disabled by default but should be enabled 
| whenever you intend to do a schema migration.
|
*/
$config['migration_enabled'] = TRUE;


/*
|--------------------------------------------------------------------------
| Migrations version
|--------------------------------------------------------------------------
|
| This is used to set migration version that the file system should be on.
| If you run $this->migration->latest() this is the version that schema will
| be upgraded / downgraded to.
|
*/
$config['migration_version'] = 1;


/*
|--------------------------------------------------------------------------
| Migrations Path
|--------------------------------------------------------------------------
|
| Path to your migrations folder.
| Typically, it will be within your application path.
| Also, writing permission is required within the migrations path.
|
*/
$config['migration_path'] = APPPATH . 'migrations/';


/* End of file migration.php */
/* Location: ./application/config/migration.php */

app_control_migration.php

<?php
    class Migration extends CI_Controller
    {
        public function __construct()
        {
            parent::__construct();
        }
        
        public function index()
        {
            $this->load->library('migration');
            if ( ! $this->migration->current())
            {
                show_error($this->migration->error_string());
            }
            else
            {
                echo "<span style='color:green;'>DB Connectivity: OK :)</span>";
            }
        }
    }

app_mig_001_create_test.php

<?php
    class Migration_Create_test extends CI_Migration 
    {

        public function up()
        {
            $this->dbforge->add_field(array(
                'id' => array(
                    'type' => 'INT',
                    'constraint' => 10,
                    'unsigned' => TRUE,
                    'auto_increment' => TRUE
                ),
                'email' => array(
                    'type' => 'VARCHAR',
                    'constraint' => '100',
                ),
                'password' => array(
                    'type' => 'VARCHAR',
                    'constraint' => '40',
                ),
                'name' => array(
                    'type' => 'VARCHAR',
                    'constraint' => '100',
                ),
            ));
            $this->dbforge->add_key('id', TRUE);
            $this->dbforge->create_table('test');
        }

        public function down()
        {
            $this->dbforge->drop_table('test');
        }
    }