Add one tag to every post, list all posts with the same tag, change the navigation bar--using dropdown toggle, and some other small changes. git commit -m'Add one tag to every post, list all posts with the same tag, change the navigation bar--using dropdown toggle, and some other small changes. !!!!PS:Now the function of new post can't work because i din't make out the post_model and tag_model.'  git commit -m'Add one tag to every post, list all posts with the same tag, change the navigation bar--using dropdown toggle, and some other small changes. !!!!PS:Now the function of new post can't work because i din't make out the post_model and tag_model.'  PS:Now the function of new post can't work because i din't make out the post_model and tag_model.