增加课程资源分离出来相关表数据迁移

db/migrate/20140812065147_add_colun_to_course_attachments.rb

@@ -0,0 +1,5 @@
+class AddColunToCourseAttachments < ActiveRecord::Migration
+  def change
+    add_column :course_attachments, :container_id, :integer, :default => 0
+  end
+end

db/migrate/20140812065417_update_course_attachments.rb

@@ -0,0 +1,29 @@
+class UpdateCourseAttachments < ActiveRecord::Migration
+  def up
+    attachments = Attachment.where(" container_type = 'Course'")
+    attachments.each do |attachment|
+      course_attachment = CourseAttachment.new
+      course_attachment.container_id = attachment.container_id
+      course_attachment.filename = attachment.filename
+      course_attachment.disk_filename = attachment.disk_filename
+      course_attachment.filesize = attachment.filesize
+      course_attachment.content_type = attachment.content_type
+      course_attachment.digest = attachment.digest
+      course_attachment.downloads = attachment.downloads
+      course_attachment.author_id = attachment.author_id
+      course_attachment.created_at = attachment.created_on
+      course_attachment.description = attachment.description
+      course_attachment.disk_directory = attachment.disk_directory
+      course_attachment.attachtype = attachment.attachtype
+      course_attachment.is_public = attachment.is_public
+      course_attachment.save(:validate => false)
+    end
+  end
+
+  def down
+    coll = CourseAttachment.all
+    coll.each do |model|
+      model.destroy
+    end
+  end
+end