if ( count($errors) == 0 )
      {
          $password = md5($password);
          $query = "SELECT * FROM users WHERE username='$username' AND password='$password'";
          $results = mysqli_query($db, $query);
          if ( mysqli_num_rows($results) == 1 )
          {
              $_SESSION['username'] = $username;
              $_SESSION['success'] = "You are now logged in";
              header('location: index.php');
          }
          else
          {
              array_push($errors, "Wrong username/password combination");
          }
      }