$_SESSION['username'] = $user['username'];
      $_SESSION['userId'] = $user['id'];
      $_SESSION['class'] = $user['class'];
      $_SESSION['firstname'] = $user['firstname'];
      $_SESSION['lastname'] = $user['lastname'];
      $_SESSION['teacher'] = $user['isTeacher'] ? true : false;
      $_SESSION['admin'] = $user['isAdmin'] ? true : false;