rails 修改字段

修改类型： 

bin/rails generate migration ChangeQrcodeFieldForShops :qrcode

class ChangeQrcodeFieldForShops < ActiveRecord::Migration
  def change
    change_column :shops, :qrcode, :string
  end
end

修改字段名称：

bin/rails generate migration ChangeSeoTitleFieldForShops :seo_title, :meta_title

class ChangeSeoTitleFieldForShops < ActiveRecord::Migration
  def change
    rename_column :shops, :seo_title, :meta_title
  end
end