Users can log in to their account

This step extends the last step - users will gain the ability to use their username and password to log in to their account via a log in screen (several forms). The main page will now contain a log in link that takes a visitor to the log in screen, which will contain a link to the sign up page as well. If a user enters their username and password they will be logged in to their account and returned to the main page. Display a toolbar that identifies the user who is currently logged in.