Renders the Post as HTML using the template specified in :attr:`html_template_path`.

        :param all_posts: An optional :class:`PostCollection` containing all of the posts in the site.
        :return: The rendered HTML as a string.

def render_item(self, all_posts):
        """
        Renders the Post as HTML using the template specified in :attr:`html_template_path`.

        :param all_posts: An optional :class:`PostCollection` containing all of the posts in the site.
        :return: The rendered HTML as a string.
        """
        index = all_posts.index(self)
        if index > 0:  # has newer posts
            newer_post = all_posts[index - 1]
        else:
            newer_post = None

        if index < len(all_posts) - 1:  # has older posts
            older_post = all_posts[index + 1]
        else:
            older_post = None
        return settings.JINJA_ENV.get_template(self.template).render(
            post=self,
            newer_post=newer_post,
            older_post=older_post,
            all_posts=all_posts,
            nav_context='post'
        )