我使用来自 Ubuntu 终端的命令创建了一个新的 Rails 应用程序：rails new testing -d mysql
然后我在 database.yml 文件中添加了 root 密码
当我运行命令 rails server 在服务器上运行应用程序时，会发生以下情况：
=> Booting WEBrick
=> Rails 3.2.13 application starting in`enter code here` development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/russian/.rvm/gems/ruby-1.9.3-p392/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `connect': Unknown database 'testing_development' (Mysql2::Error)
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `initialize'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `new'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `mysql2_connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /home/russian/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /home/russian/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/activerecord-3.2.13/lib/active_record/railtie.rb:88:in `block in <class:Railtie>'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
from /home/russian/.rvm/gems/ruby-1.9.3-p392`enter code here`/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /home/russian/testing/config/environment.rb:5:in `<top (required)>'
from /home/russian/testing/config.ru:3:in `require'
from /home/russian/testing/config.ru:3:in `block in <main>'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
from /home/russian/testing/config.ru:in `new'
from /home/russian/testing/config.ru:in `<main>'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands/server.rb:46:in `app'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands/server.rb:70:in `start'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:55:in `block in <top (required)>'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
from /home/russian/.rvm/gems/ruby-1.9.3-p392/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
Can anyone help me with the problem?