我找不到解决方案。我想在我的Web应用程序中创建新用户（使用Devise）。请阅读以下注释：
我目前的操作系统：Ubuntu 15 以前的操作系统：Linux Mint （在Mac OS X上它可以正常工作）
Terminal log:
Started POST "/users" for 127.0.0.1 at 2016-03-04 00:40:32 +0300
Processing by Users::RegistrationsController#create as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"OmTevxMT8IYxO8fcWHJU75gsLhVlj6/dLctvU2PhIWnlsEZ2B0p0iCQClVmPbRKBBauBKfjwv1hRnP8kTC0sxg==", "user"=>{"name"=>"test", "surname"=>"test", "email"=>"test@test.ru", "password"=>"[FILTERED]", "password_confirmation"=>"[FILTERED]"}, "commit"=>"Зарегистрироваться"}
(0.3ms) BEGIN
User Exists (0.7ms) SELECT 1 AS one FROM `users` WHERE `users`.`email` = BINARY 'test@test.ru' LIMIT 1
SQL (0.6ms) INSERT INTO `users` (`email`, `encrypted_password`, `name`, `surname`, `created_at`, `updated_at`) VALUES ('test@test.ru', '$2a$10$sY490xgy8sHCFJxfY2B80OSFV7s.p0qg8R03ZPLGjzGYqou8Lz6xC', 'test', 'test', '2016-03-03 21:40:32.488474', '2016-03-03 21:40:32.488474')
(44.3ms) COMMIT
Completed 500 Internal Server Error in 201ms
ArgumentError - argument out of range:
activesupport (4.2.0) lib/active_support/values/time_zone.rb:350:in `parse'
activesupport (4.2.0) lib/active_support/core_ext/string/zones.rb:9:in `in_time_zone'
activerecord (4.2.0) lib/active_record/attribute_methods/time_zone_conversion.rb:15:in `type_cast_from_user'
activerecord (4.2.0) lib/active_record/attribute.rb:100:in `type_cast'
activerecord (4.2.0) lib/active_record/attribute.rb:42:in `original_value'
activerecord (4.2.0) lib/active_record/attribute.rb:37:in `value'
activerecord (4.2.0) lib/active_record/attribute.rb:46:in `value_for_database'
activerecord (4.2.0) lib/active_record/attribute_methods/dirty.rb:164:in `store_original_raw_attribute'
activerecord (4.2.0) lib/active_record/attribute_methods/dirty.rb:93:in `write_attribute'
activerecord (4.2.0) lib/active_record/attribute_methods.rb:50:in `__temp__c6163747f5379676e6f596e6f59607'
devise (3.5.5) lib/devise/models/trackable.rb:24:in `update_tracked_fields'
devise (3.5.5) lib/devise/models/trackable.rb:32:in `update_tracked_fields!'
devise (3.5.5) lib/devise/hooks/trackable.rb:7:in `block in '
warden (1.2.6) lib/warden/hooks.rb:14:in `block in _run_callbacks'
warden (1.2.6) lib/warden/hooks.rb:9:in `_run_callbacks'
warden (1.2.6) lib/warden/manager.rb:51:in `_run_callbacks'
warden (1.2.6) lib/warden/proxy.rb:179:in `set_user'
devise (3.5.5) lib/devise/controllers/sign_in_out.rb:43:in `sign_in'
devise (3.5.5) app/controllers/devise/registrations_controller.rb:106:in `sign_up'
devise (3.5.5) app/controllers/devise/registrations_controller.rb:22:in `create'
app/controllers/users/registrations_controller.rb:12:in `create'
actionpack (4.2.0) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.2.0) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.0) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.0) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.0) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:234:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:169:in `block in halting'
activesupport (4.2.0) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0) lib/active_support/callbacks.rb:151:in `block in halting_and_conditional'
activesupport (4.2.0) lib/active_support/callbacks.rb:92:in `_run_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:734:in `_run_process_action_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action'
activesupport (4.2.0) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.0) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.0) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.0) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.0) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.0) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.0) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.0) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.0) lib/action_controller/metal.rb:195:in `dispatch'
actionpack (4.2.0) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.0) lib/action_controller/metal.rb:236:in `block in action'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:73:in `dispatch'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:42:in `serve'
actionpack (4.2.0) lib/action_dispatch/routing/mapper.rb:49:in `serve'
actionpack (4.2.0) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.0) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.0) lib/action_dispatch/routing/route_set.rb:802:in `call'
warden (1.2.6) lib/warden/manager.rb:35:in `block in call'
warden (1.2.6) lib/warden/manager.rb:34:in `call'
rack (1.6.4) lib/rack/etag.rb:24:in `call'
rack (1.6.4) lib/rack/conditionalget.rb:38:in `call'
rack (1.6.4) lib/rack/head.rb:13:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.4) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.4) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.0) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:647:in `call'
activerecord (4.2.0) lib/active_record/migration.rb:378:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.0) lib/active_support/callbacks.rb:88:in `_run_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:734:in `_run_call_callbacks'
activesupport (4.2.0) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
better_errors (2.1.1) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (2.1.1) lib/better_errors/middleware.rb:57:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
web-console (2.3.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (2.3.0) lib/web_console/middleware.rb:18:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.0) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.0) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.0) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.0) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.0) lib/rails/rack/logger.rb:20:in `call'
quiet_assets (1.1.0) lib/quiet_assets.rb:27:in `call_with_quiet_assets'
actionpack (4.2.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.4) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.4) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.0) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.4) lib/rack/lock.rb:17:in `call'
actionpack (4.2.0) lib/action_dispatch/middleware/static.rb:113:in `call'
rack (1.6.4) lib/rack/sendfile.rb:113:in `call'
railties (4.2.0) lib/rails/engine.rb:518:in `call'
railties (4.2.0) lib/rails/application.rb:164:in `call'
rack (1.6.4) lib/rack/content_length.rb:15:in `call'
puma (2.16.0) lib/puma/server.rb:557:in `handle_request'
puma (2.16.0) lib/puma/server.rb:404:in `process_client'
puma (2.16.0) lib/puma/server.rb:270:in `block in run'
puma (2.16.0) lib/puma/thread_pool.rb:106:in `block in spawn_thread'
我已对模型添加了更改，但我的错误是相同的：
class Something < ActiveRecord::Base
validate :important_date_is_valid_datetime, on: :create
validates :important_date, presence: true
private
def important_date_is_valid_datetime
if (DateTime.parse(important_date.to_s()) rescue ArgumentError) == ArgumentError then
errors.add(:important_date, 'must be a valid datetime')
end
end
end
另外，我在表单中添加了下一个代码：
class Something < ActiveRecord::Base
validate :important_date_is_valid_datetime, on: :create
validates :important_date, presence: true
private
def important_date_is_valid_datetime
if (DateTime.parse(important_date.to_s()) rescue ArgumentError) == ArgumentError then
errors.add(:important_date, 'must be a valid datetime')
end
end
end