This is the newest version.(11/4)
Function: 1. enable link to other pages 2. build the simple ui for user to fill in personal info like gender and birthday
Problems: 1. register page's required attribute does not work after adding link 2. Some project logic may need to be change. For example, new user info should be link to register and update user info should be linked to log in. Backend should probably get user's info by log in info and then update personal info such as birthday and gender