修改课程退出的权限

app/views/layouts/base_courses.html.erb

@@ -43,7 +43,9 @@
 											<div class="info_font" style=" word-wrap: break-word; word-break: break-all">
 												<%=  @project.name %>
 											</div>
+											<% unless @course.teacher.id == User.current.id%>
 											<%= join_in_course(@project, User.current)%>
+											<% end %>
 											</td>
 										</tr>
 									</table>