几天前，我为 rails 创建了一个迁移以添加 Paperclip 头像，但最终走向了不同的方向。作为 Rails 的新手，我不知道像我一样删除迁移文件是多么糟糕的想法。
我的应用程序在本地运行良好，但运行时heroku run rake db:migrate我得到这个：
undefined method `attachment' for #<ActiveRecord::ConnectionAdapters::Table:0x000000046092e0>
这是因为它正在尝试运行一个名为 的迁移AddAttachmentAvatarToVenues，这是我愚蠢地删除的迁移。
它还为已删除的迁移中指定的头像添加了列schema.rb，但我创建了一个新的迁移来摆脱这些。新的迁移摆脱了它们，但没有改变 heroku 迁移错误。
知道如何解决这个问题吗？我已经做了很多谷歌搜索和环顾四周，虽然有很多人有类似的错误，但他们主要是他们使用的命令有问题。
这是在我的 heroku 迁移中尝试删除迁移后的输出。
== AddAttachmentAvatarToVenues: migrating ====================================
-- change_table(:venues)
rake aborted!
An error has occurred, this and all later migrations canceled:
undefined method `attachment' for #<ActiveRecord::ConnectionAdapters::Table:0x00000003bdb7c8>
/app/db/migrate/20130206222434_add_attachment_avatar_to_venues.rb:4:in `block in up'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/schema_statements.rb:243:in `change_table'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:466:in `block in method_missing'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:438:in `block in say_with_time'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:438:in `say_with_time'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:458:in `method_missing'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:334:in `method_missing'
/app/db/migrate/20130206222434_add_attachment_avatar_to_venues.rb:3:in `up'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:370:in `up'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:410:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:410:in `block in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:129:in `with_connection'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:389:in `migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:528:in `migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:720:in `block (2 levels) in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in `call'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in `block in ddl_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/transactions.rb:208:in `transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:775:in `ddl_transaction'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:719:in `block in migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:700:in `each'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:700:in `migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:570:in `up'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/migration.rb:551:in `migrate'
/app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.2.11/lib/active_record/railties/databases.rake:179:in `block (2 levels) in <top (required)>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)
我确实看到了输出有什么问题，我只是不确定如何在不弄乱它的情况下修复它。
编辑：这是文件结构的一些截图：
（这两个名称相似的原因是因为我忘记删除一列，但这是在我遇到此问题之后并且没有影响它）
编辑2：
这是我的 git 历史记录中已删除的迁移。在此之后我添加了更多频道。它们只是几个字符串，但如果这能有所作为，我会找到一个更新的版本。
class AddAttachmentAvatarToVenues < ActiveRecord::Migration
def self.up
change_table :venues do |t|
t.attachment :avatar
end
end
def self.down
drop_attached_file :venues, :avatar
end
end
提前致谢！