迁移

db/migrate/20190622060005_remove_shixun_long_text_for_shixuns.rb

@@ -1,6 +1,6 @@
 class RemoveShixunLongTextForShixuns < ActiveRecord::Migration[5.2]
   def change
-    if Shixun.first.description.present?
+    if Shixun.first.has_attribute?(:description)
       remove_columns :shixuns, :description, :propaedeutics, :evaluate_script
     end
   end