公告栏排序功能

app/controllers/courses_controller.rb

@@ -317,7 +317,7 @@ class CoursesController < ApplicationController
     inform = Inform.new(container: @course)
     inform.name = params[:name]
     inform.description = params[:description]
-    inform.position = @course.informs.maximum(:position) + 1
+    inform.position = @course.informs.maximum(:position).to_i + 1
     inform.save!
     normal_status("创建成功")
   end