删除每个页面上单独查询公告的逻辑，改为使用 templatetag 实现。

template/src/oj/announcement/_announcement_panel.html

@@ -1,3 +1,4 @@
+{% load announcement_list %}
 <div class="panel panel-info">
     <div class="panel-heading">
         <h3 class="panel-title">
@@ -5,8 +6,9 @@
             公告
         </h3></div>
     <div class="panel-body">
+    {% public_announcement_list as announcements %}
         {% if announcements %}
-            {% for item in announcements %}
+            {% for item in announcements%}
             <p>{{ forloop.counter }}.&nbsp;&nbsp;<a href="/announcement/{{ item.id }}/" target="_blank">{{ item.title }}</a>
             </p>
             {% endfor %}

template/src/oj/submission/my_submissions_list.html

@@ -3,7 +3,7 @@
 {% block body %}
 {% load submission %}
 <div class="container main">
-    <div class="col-md-9 col-lg-9">
+    <div class="col-md-12 col-lg-12">
         <table class="table table-striped">
             <thead>
             <tr>
@@ -92,8 +92,6 @@
         <p>你还没有提交记录!</p>
         {% endif %}
     </div>
-    <div class="col-md-3 col-lg-3">
-        {% include "oj/announcement/_announcement_panel.html" %}
-    </div>
+
 </div>
 {% endblock %}