modify school statisitc teacher shixun list no

app/views/colleges/_student_shixun.html.erb

@@ -11,11 +11,7 @@
 <% @students.each_with_index do |student, index| %>
   <tr>
     <td class="pl20 pr20">
-      <% if index < 3 %>
+      <%= index + 1 %>
-        <img src="/images/educoder/competition/<%= index + 1 %>.png" width="18px" height="22px" class="mt8"/></td>
-      <% else %>
-        <%= index + 1 %>
-      <% end %>
       </td>
       <td class="color-dark">
         <a href="<%= user_path(student) %>" target="_blank" class="task-hide" style="max-width: 84px;"><%= student.show_real_name %></a>