我想继续编写铁路应用程序，但是当我尝试启动服务器时出现以下错误rails s。
当我有一个全新的目录（它在那里使用 sqlite3）时，我的导轨安装似乎工作正常。我也可能安装了所有东西，xcode，自制软件，RVM ......
操作系统：OS X，1.8.2
有什么想法可以解决这个错误吗？
/Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `connect': Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2) (Mysql2::Error)
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `initialize'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `new'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `mysql2_connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /Users/myself/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /Users/myself/.rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/model_schema.rb:308:in `clear_cache!'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activerecord-3.2.9/lib/active_record/railtie.rb:97:in `block (2 levels) in <class:Railtie>'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:418:in `_run__4072264347074867870__prepare__1617522906049658136__callbacks'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:405:in `__run_callback'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:385:in `_run_prepare_callbacks'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/callbacks.rb:81:in `run_callbacks'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/reloader.rb:48:in `prepare!'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/application/finisher.rb:47:in `block in <module:Finisher>'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/initializable.rb:30:in `instance_exec'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/initializable.rb:30:in `run'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/initializable.rb:55:in `block in run_initializers'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/initializable.rb:54:in `each'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/initializable.rb:54:in `run_initializers'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/application.rb:136:in `initialize!'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /Users/myself/events/config/environment.rb:5:in `<top (required)>'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:251:in `require'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:251:in `block in require'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:236:in `load_dependency'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/activesupport-3.2.9/lib/active_support/dependencies.rb:251:in `require'
from /Users/myself/events/config.ru:4:in `block in <main>'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize'
from /Users/myself/events/config.ru:1:in `new'
from /Users/myself/events/config.ru:1:in `<main>'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/builder.rb:40:in `eval'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/builder.rb:40:in `parse_file'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/server.rb:200:in `app'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/commands/server.rb:46:in `app'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/server.rb:301:in `wrapped_app'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.1/lib/rack/server.rb:252:in `start'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/commands/server.rb:70:in `start'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/commands.rb:55:in `block in <top (required)>'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/commands.rb:50:in `tap'
from /Users/myself/.rvm/gems/ruby-1.9.3-p327/gems/railties-3.2.9/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'