User feature: Sign-in as a registered user

as a registered user, I want to log in to my account, so I can use this music web app

technical details

• in the landing (home) page functionbar, there will be a sign-in button for registered user to log in
• a new sign-in/sign-up window opens up after clicking the sign-in button
• user requires its personal information such as username and password during the log-in process
• there will be a buttion for user to confirm that they want to logging into the web app