Add dummy content when running migrations

Hi all, I'd like some feedback please, if possible. I'm using CI v3 and I was wondering whether there's a way I could enter some dummy content on the tables I generate running through Migrations.

For instance when I run this migration

PHP Code:

class Migration_Add_blog extends CI_Migration {

        public function up()
        {
                $this->dbforge->add_field(array(
                        'blog_id' => array(
                                'type' => 'INT',
                                'constraint' => 5,
                                'unsigned' => TRUE,
                                'auto_increment' => TRUE
                        ),
                        'blog_title' => array(
                                'type' => 'VARCHAR',
                                'constraint' => '100',
                        ),
                        'blog_description' => array(
                                'type' => 'TEXT',
                                'null' => TRUE,
                        ),
                ));
                $this->dbforge->add_key('blog_id', TRUE);
                $this->dbforge->create_table('blog');
        }

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


Is there also a way I could enter a few dummy blog posts to see as an example ?

One additional question regarding the Migrations. If I have the migrations types set as

PHP Code:

$config['migration_type'] = 'timestamp'; 


when I run this command

PHP Code:

$this->migration->version(5); 


do I have to enter the full timestamp or just the number version and if so how can I get the timestamp ?

Thanks in advance