<?php

if(array_key_exists('firstname', $_POST) && array_key_exists('lastname', $_POST) && array_key_exists('email', $_POST) ) {

    $db = mysqli_connect("localhost","","","") or die ("Connection failed!");

    $query = ('INSERT INTO 'Users' (firstname, lastname, email, pass, cpass) VALUES (?, ?, ?, ?, ?)');
    $stmt = $db->prepare($query);
    $stmt->bind_param("sssss", $_POST['firstname'], $_POST['lastname'], $_POST['email'], $_POST['pass'], $_POST['cpass']);

  if ($stmt->execute()) {
    'Yay!! New user was added.'
  } else {
    die('Oops we could not add your deatils to the user database.');
  }

  $db->close();

}

?>