add new Tag model to bookmarks
make bookmarks model more readable
add new view for user to save bookmarks
replace custom-made login with django built-in login
after login, user will be now be redirected to previous url
add new template to show a list of bookmarks
improve user_pages
update user_page view
add tag_page to show all the bookmarks for a specific tag
add tag_cloud_page to view a cloud of tags by its weight
add csrf_token in a few forms
add "escape" and "urlencode" to imporve site security
add search page
improve search page
add ajax support to search page
search_page now only avaliable when user log in
enable user to edit the bookmark
add in-plce bookmark editting
improve in-place bookmark editting
fixed ajax forbiden error