在def get_thread(request)中
thread_html = render_to_string("news/news_thread.html", {"thread": news.get_thread(), 'request': request})
这边需要把reuqest返回回去不然前面news_thread模板中的
 {% if request.user.username == reply.user.username %}
                   <a href="{% url 'news:delete_news' reply.pk %}">
                     <i class="fa fa-times pull-right" aria-hidden="true" title="点击删除这条动态"></i>
                   </a>
 {% endif %}
 不会判断 导致评论无法删除