我正在帮助一个朋友修改他提供的 Rails 网站，我对 Rails 和 Ruby 的了解只有表面的知识，但足以完成他需要我做的事情。麻烦的是我在设置我的开发环境时遇到了这个错误，我无法弄清楚。
跑步：
$ rake db:migrate --trace
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
development database is not configured
/var/lib/gems/1.8/gems/activerecord-2.3.14/lib/active_record/connection_adapters/abstract/connection_specification.rb:62:in `establish_connection'
/var/lib/gems/1.8/gems/activerecord-2.3.14/lib/active_record/connection_adapters/abstract/connection_specification.rb:55:in `establish_connection'
/home/rory/projects/project_server/ruby_lib/project/lib/project/model.rb:21:in `init'
/home/rory/projects/project_server/ruby_lib/project/lib/project/model.rb:15:in `each'
/home/rory/projects/project_server/ruby_lib/project/lib/project/model.rb:15:in `init'
/home/rory/projects/project_server/ruby_lib/project/lib/project/project.rb:218:in `init' /home/rory/projects/project_server/rails/project_web/config/environments/development.rb:28:in `load_environment'
/var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:386:in `load_environment'
/var/lib/gems/1.8/gems/activesupport-2.3.14/lib/active_support/core_ext/kernel/reporting.rb:11:in `silence_warnings'
/var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:379:in `load_environment'
/var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:137:in `process'
/var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:113:in `send'
/var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:113:in `run'
/home/rory/projects/project_server/rails/project_web/config/environment.rb:9
/usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:53:in `gem_original_require'
/usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:53:in `require'
/var/lib/gems/1.8/gems/activesupport-2.3.14/lib/active_support/dependencies.rb:182:in `require'
/var/lib/gems/1.8/gems/activesupport-2.3.14/lib/active_support/dependencies.rb:547:in `new_constants_in'
/var/lib/gems/1.8/gems/activesupport-2.3.14/lib/active_support/dependencies.rb:182:in `require'
/var/lib/gems/1.8/gems/rails-2.3.14/lib/tasks/misc.rake:4
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain'
/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:607:in `invoke_prerequisites'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `each'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:604:in `invoke_prerequisites'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:596:in `invoke_with_call_chain'
/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling'
/var/lib/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run'
/var/lib/gems/1.8/gems/rake-0.8.7/bin/rake:31
/usr/local/bin/rake:19:in `load'
/usr/local/bin/rake:19
跑步
$ rake db:create
按预期工作，在 mysql 中创建数据库。
我已经检查了 database.yml 是否正确缩进了空格而不是制表符。已安装所有必需的库。
该站点运行（因此我在我的开发环境中运行）：
红宝石 1.8.7 轨道 2.3.14
数据库.yml：
development:
adapter: mysql
database: development
username: developer
password: devpass
socket: /var/run/mysqld/mysqld.sock