*	Only valid users can access a quiz, not anonymous users.
*	Both students and teachers have registations also.
*	Every quiz has score and certificates too.
*	The app have a leaderboard for students.
*	A student have able to login and see which questions I answered correct and wrong.
*	As a teacher I should be able to login and review the performance of my students. 
*	Also timer for quizes.
*	A select html file for select user teacher or student.
*	Also student select html for start quiz or check answers.