CodeIgniter database insert not inserting

I'm using CodeIgniter to add a record into the database.

database.php:

$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'test_user';
$db['default']['password'] = 'test_pwd';
$db['default']['database'] = 'test_db';
$db['default']['dbdriver'] = 'mysqli';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = FALSE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = '';
$db['default']['char_set'] = 'utf8';
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['swap_pre'] = '';
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;

insert function in model.php:

public function set_news()
{
    $this->load->helper('url');

    $slug = url_title($this->input->post('title'), 'dash', TRUE);

    $data = array(
        'title' => $this->input->post('title'),
        'slug' => $slug,
        'text' => $this->input->post('text')
    );

    $this->output->enable_profiler(TRUE);
    return $this->db->insert('news', $data);
}

I get this output when set_news() runs:

  DATABASE:  test_db QUERIES: 1  (Hide)
0.0005       INSERT INTO `news` (`title`, `slug`, `text`) VALUES ('come on', 'come-on', 'work')

However, when I view the table in the database, it still has zero rows. Any idea what's going on? Thanks!