This is my stack trace:
mysql2 (0.3.15) lib/mysql2/client.rb:67:in `connect'
mysql2 (0.3.15) lib/mysql2/client.rb:67:in `initialize'
activerecord (4.0.0)
lib/active_record/connection_adapters/mysql2_adapter.rb:18:in `new'
activerecord (4.0.0)
lib/active_record/connection_adapters/mysql2_adapter.rb:18:in
`mysql2_connection'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:440:in
`new_connection'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:450:in
`checkout_new_connection'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:421:in
`acquire_connection'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:356:in
`block in checkout'
C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/monitor.rb:211:in
`mon_synchronize'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:355:in
`checkout'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in
`block in connection'
C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/monitor.rb:211:in
`mon_synchronize'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in
`connection'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:546:in
`retrieve_connection'
activerecord (4.0.0) lib/active_record/connection_handling.rb:79:in
`retrieve_connection'
activerecord (4.0.0) lib/active_record/connection_handling.rb:53:in
`connection'
activerecord (4.0.0) lib/active_record/query_cache.rb:51:in
`restore_query_cache_settings'
activerecord (4.0.0) lib/active_record/query_cache.rb:43:in `rescue in
call'
activerecord (4.0.0) lib/active_record/query_cache.rb:32:in `call'
activerecord (4.0.0)
lib/active_record/connection_adapters/abstract/connection_pool.rb:626:in
`call'
activerecord (4.0.0) lib/active_record/migration.rb:369:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in
`block in call'
activesupport (4.0.0) lib/active_support/callbacks.rb:373:in
`_run__1069024569__call__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in
`run_callbacks'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in
`call'
actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in
`call'
actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in
`call'
actionpack (4.0.0)
lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.0)
lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block
in tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in
`tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in
`tagged'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in
`call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0)
lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0) lib/rails/engine.rb:511:in `call'
railties (4.0.0) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
rack (1.5.2) lib/rack/handler/webrick.rb:60:in `service'
C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/webrick/httpserver.rb:138:in
`service'
C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/webrick/httpserver.rb:94:in
`run'
C:/RailsInstaller/Ruby2.0.0/lib/ruby/2.0.0/webrick/server.rb:295:in
`block in start_thread'