迁移课堂分班position

db/migrate/20190720062632_migrate_course_group_position.rb

@@ -0,0 +1,11 @@
+class MigrateCourseGroupPosition < ActiveRecord::Migration[5.2]
+  def change
+    Course.find_each do |course|
+      position = 1
+      course.course_groups.reorder("CONVERT(course_groups.name USING gbk) COLLATE gbk_chinese_ci ASC").find_each do |group|
+        group.update_attribute(:position, position)
+        position += 1
+      end
+    end
+  end
+end