Untitled

$result = pg_query("INSERT INTO users VALUES('','".$username."','".md5($password)."')");

$result = pg_query($pdo, "INSERT INTO users VALUES('','".$username."','".md5($password)."')");

<?php
 try
 {
   $pdo = new PDO('pgsql:host=localhost; port=5432; dbname=Website', 'postgres', '');
   $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
 }

<html>
<head>
<title>Register - Friend System</title>
<link rel='stylesheet' href="style.css" />
<head>
<body>
<?php include 'connect.php';?>

<?php include 'functions.php' ?>

<?php include 'header.php' ?>

<div class='container'>
<h3>Register a new account</h3>
<form method='post'>
<?php
   if(isset($_POST['submit'])){
       $username = $_POST['username'];
       $password = $_POST['password'];

       if(empty ($username) or empty ($password)){
           $message = "Fields Empty, Please re-check the form";
       } else {
         $result = pg_query("INSERT INTO users VALUES('','".$username."','".md5($password)."')");
         $message = "Registration completed! You can now log in!";
       }
       echo "<div class='box'>$message</div>";
   }
   ?>
User Name: <br/>
<input type='text' name='username' autocomplete='off' />
<br/><br/>
Password: <br/>
<input type='password' name='password' />
<br/><br/>
<input type='submit' name='submit' value='Register' />
</form>
</div>