Ruby on rails heroku:rake db:迁移mongoDB失败

运行heroku run rake db:migrate并获取错误：

Running `rake db:migrate` attached to terminal... up, run.9259
DEPRECATION WARNING: railtie_name is deprecated and has no effect. (called from <top (required)> at /app/config/application.rb:10)
WARNING: Global access to Rake DSL methods is deprecated.  Please include
    ...  Rake::DSL into classes and modules which use the Rake DSL methods.
WARNING: DSL method Quora::Application#task called at /app/vendor/bundle/ruby/1.9.1/gems/railties-3.0.5/lib/rails/application.rb:214:in `initialize_tasks'
rake aborted!
Database should be a Mongo::DB, not NilClass.

我曾尝试寻找解决方案或任何方向来解决问题，但没有成功。我做错了什么

编辑：我将

include Rake:：DSL

添加到我的Rakefile中，现在初始警告消失了，但我仍然得到：

heroku run rake db:migrate
Running `rake db:migrate` attached to terminal... up, run.4751
DEPRECATION WARNING: railtie_name is deprecated and has no effect. (called from <top (required)> at /app/config/application.rb:11)
rake aborted!
Database should be a Mongo::DB, not NilClass.

Tasks: TOP => db:migrate => environment
(See full trace by running task with --trace)

heroku运行rake数据库：迁移
正在运行附加到终端的“rake db:migrate”。。。起来，跑
弃用警告：railtie_名称已弃用，且无效。（从at/app/config/application.rb:11调用）
雷克流产了！
数据库应该是Mongo:：DB，而不是NilClass。
任务：TOP=>db:migrate=>environment
（通过使用--trace运行任务查看完整跟踪）

我想你错过了：

adapter: mongodb

以下是我对postgres database.yml的设置：

development: 
  adapter: postgresql
  encoding: unicode
  database: db
  pool: 50
  username: user
  password: pwd
  host: localhost

您可能还想查看此帖子：

---

hey@ant我相信mongoid是一个完全的替代品，而不是适配器

development: 
  adapter: postgresql
  encoding: unicode
  database: db
  pool: 50
  username: user
  password: pwd
  host: localhost