[story#005+#008]xuhao&xuxiaojuan:Modify login.html to login.erb.
[story#008][xuhao and xuxiaojuan]: add the information checking function
[story#006][xuhao and xuxiao juan] merge the conflict in the product_spec file
[stroy#006][xuhao and xuxiaojuan]: add the logout function and change the login html to access the custom login
[story#011][xuhao and xuxiaojuan]: show the user name in all pages when login
[xuhao and xuxiaojuan]: merge the conflict in products_spect.rb and all the erb files