$db_connection = pg_connect("host=localhost dbname=levantiu_levantium user=levantiu_levantium_app password=mypassword");

$dsn = "pgsql:host=localhost;dbname=levantiu_levantium";
$options = [
    PDO::ATTR_EMULATE_PREPARES   => false, // turn off emulation mode for "real" prepared statements
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION, //turn on errors in the form of exceptions
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC, //make the default fetch be an associative array
];
try {
    $pdo = new PDO($dsn, "levantiu_levantium_app", "mypassword", $options);
    echo 'conectado!';
} catch (Exception $e) {
    var_dump($e->getMessage());
    exit('Something weird happened'); //something a user can understand
}