小编Rav*_*iya的帖子

我正在使用Heroku上托管的Rails 5.1,我使用以下命令来迁移我的数据库:

heroku run rake db:migrate -a [my app name]

所有迁移本身都正确完成:

SQL (1.6ms)  INSERT INTO "schema_migrations" ("version") VALUES ($1) RETURNING "version"  [["version", "20180504164326"]]
   (2.1ms)  COMMIT
Migrating to AddPinToStaff (20180519024721)
   (1.5ms)  BEGIN
== 20180519024721 AddPinToStaff: migrating ====================================
-- add_column(:staff, :pin_number, :string)
   (4.2ms)  ALTER TABLE "staff" ADD "pin_number" character varying
   -> 0.0045s
== 20180519024721 AddPinToStaff: migrated (0.0046s) ===========================

这是我创建的最后一个迁移文件,所以这一切似乎都有效.然后,这运行:

SQL (1.6ms)  INSERT INTO "schema_migrations" ("version") VALUES ($1) RETURNING "version"  [["version", "20180519024721"]]
(2.4ms)  COMMIT
ActiveRecord::InternalMetadata Load (1.7ms)  SELECT  "ar_internal_metadata".* FROM "ar_internal_metadata" WHERE "ar_internal_metadata"."key" …

我收到以下错误消息,不知道如何解决它.有人可以帮忙吗？

NoMethodError:未定义的方法`needs_migration？' 对于ActiveRecord :: Migrator:Class

这是config.ru代码:

require './config/environment'

if ActiveRecord::Migrator.needs_migration?
  raise 'Migrations are pending. Run `rake db:migrate` to resolve the issue.'
end

use Rack::MethodOverride

use UsersController
use ArtworkController
run ApplicationController