Ruby on rails Rake中止：Don'；我不知道rails安装后如何迁移

我正在尝试使用新安装的rails版本。根据我使用rails构建的模型创建项目并迁移数据库。我遇到了一个不知道如何构建任务“db:：migrate”的错误

我跑了

删除所有宝石：
'gem list--无版本'中的i的

；执行gem卸载-aIx$i；完成

安装rails并创建新项目

sudogem安装rails

rails新测试api

rails生成控制器用户索引

rails生成模型用户名：string

这就是我的设置

然后我执行了迁移数据库的方法：

rakedb:：migrate

这是我的输出：

rake db::migrate
rake aborted!
Don't know how to build task 'db::migrate'
/Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:241:in `load'
/Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:241:in `block in load'
/Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:232:in `load_dependency'
/Library/Ruby/Gems/2.0.0/gems/activesupport-4.1.6/lib/active_support/dependencies.rb:241:in `load'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/command_wrapper.rb:40:in `call'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application.rb:180:in `block in serve'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application.rb:153:in `fork'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application.rb:153:in `serve'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application.rb:128:in `block in run'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application.rb:122:in `loop'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application.rb:122:in `run'
/Library/Ruby/Gems/2.0.0/gems/spring-1.1.3/lib/spring/application/boot.rb:18:in `<top (required)>'
-e:1:in `<main>'
(See full trace by running task with --trace)

rake数据库：：迁移
雷克流产了！
不知道如何构建任务“db:：migrate”
/Library/Ruby/Gems/2.0.0/Gems/activesupport-4.1.6/lib/active\u support/dependencies.rb:241:in'load'
/Library/Ruby/Gems/2.0.0/Gems/activesupport-4.1.6/lib/active\u support/dependencies.rb:241:in'block in load'
/Library/Ruby/Gems/2.0.0/Gems/activesupport-4.1.6/lib/active\u-support/dependencies.rb:232:in'load\u-dependency'
/Library/Ruby/Gems/2.0.0/Gems/activesupport-4.1.6/lib/active\u support/dependencies.rb:241:in'load'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/command_wrapper.rb:40:in'call'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application.rb:180:in'block in service'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application.rb:153:in'fork'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application.rb:153:in'serve'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application.rb:128:in'block in run'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application.rb:122:in'loop'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application.rb:122:in'run'
/Library/Ruby/Gems/2.0.0/Gems/spring-1.1.3/lib/spring/application/boot.rb:18:in`'
-e:1:in`'
（通过使用--trace运行任务查看完整跟踪）

我找到了一个解决方案。如果我刚刚刷新了服务器上的页面，我会发现：

这给了我运行此命令的答案：

bin/rake db:migrate RAILS_ENV=development