add img's static url to app.yaml
use jinja to set a template, containing header & footer; login page is on the way
update footer information
almost finish the layout of new login page
update footer; change background color; make buttons in header UPPERCASE
redone the log in page, pretty beautiful now~
remove some unused css
redone signup page, pretty beautiful~
now login & signup button in header is available
add gradient to login & signup buttons in header