#1297修复学生能看到发布通知按钮的BUG

2.增加课程是否对学生开发的数据迁移
 3.页面代码整理
 解决方案：增加当前登录用户是否在课程有发布通知权限的判断

app/views/news/_course_news.html.erb

@@ -64,12 +64,12 @@
 <span style="font-size: 16px; border-bottom:1px solid #f0f0f0; margin-right: 15px;">
 	<%= label_tips %>
 </span>
-<%= link_to(btn_tips,
-            new_course_news_path(@course),
-            :class => 'icon icon-add',
-            :onclick => 'showAndScrollTo("add-news", "news_title"); return false;') %>
 
 <% if @course && User.current.allowed_to?(:manage_news, @course) %>
+    <%= link_to(btn_tips, new_course_news_path(@course),
+                :class => 'icon icon-add',
+                :onclick => 'showAndScrollTo("add-news", "news_title"); return false;') %>
+
     <div id="add-news" class="add_frame" style="display:none;">
       <%= labelled_form_for @news, :url => course_news_index_path(@course),
                             :html => {:id => 'news-form', :multipart => true} do |f| %>

db/migrate/20140930072719_add_open_student_to_course.rb

@@ -0,0 +1,5 @@
+class AddOpenStudentToCourse < ActiveRecord::Migration
+  def change
+    add_column :courses, :open_student, :integer, :default => 0
+  end
+end