甚至正在发送激活邮件，但弹出此错误。
完整的跟踪是：
activerecord (3.2.2) lib/active_record/persistence.rb:104:in `save!'
activerecord (3.2.2) lib/active_record/validations.rb:56:in `save!'
activerecord (3.2.2) lib/active_record/attribute_methods/dirty.rb:33:in `save!'
activerecord (3.2.2) lib/active_record/transactions.rb:246:in `block in save!'
activerecord (3.2.2) lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
activerecord (3.2.2) lib/active_record/transactions.rb:208:in `transaction'
activerecord (3.2.2) lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
activerecord (3.2.2) lib/active_record/transactions.rb:246:in `save!'
sorcery (0.7.7) lib/sorcery/model/submodules/user_activation.rb:115:in `activate!'
app/controllers/users_controller.rb:34:in `activate'
actionpack (3.2.2) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (3.2.2) lib/abstract_controller/base.rb:167:in `process_action'
actionpack (3.2.2) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (3.2.2) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
activesupport (3.2.2) lib/active_support/callbacks.rb:414:in `_run__78363924__process_action__67485199__callbacks'
activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.2) lib/active_support/callbacks.rb:385:in `_run_process_action_callbacks'
activesupport (3.2.2) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.2) lib/abstract_controller/callbacks.rb:17:in `process_action'
actionpack (3.2.2) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (3.2.2) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
activesupport (3.2.2) lib/active_support/notifications.rb:123:in `block in instrument'
activesupport (3.2.2) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (3.2.2) lib/active_support/notifications.rb:123:in `instrument'
actionpack (3.2.2) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
actionpack (3.2.2) lib/action_controller/metal/params_wrapper.rb:205:in `process_action'
activerecord (3.2.2) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (3.2.2) lib/abstract_controller/base.rb:121:in `process'
actionpack (3.2.2) lib/abstract_controller/rendering.rb:45:in `process'
actionpack (3.2.2) lib/action_controller/metal.rb:203:in `dispatch'
actionpack (3.2.2) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
actionpack (3.2.2) lib/action_controller/metal.rb:246:in `block in action'
actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:67:in `call'
actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:67:in `dispatch'
actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:30:in `call'
journey (1.0.3) lib/journey/router.rb:68:in `block in call'
journey (1.0.3) lib/journey/router.rb:56:in `each'
journey (1.0.3) lib/journey/router.rb:56:in `call'
actionpack (3.2.2) lib/action_dispatch/routing/route_set.rb:594:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
rack (1.4.5) lib/rack/etag.rb:23:in `call'
rack (1.4.5) lib/rack/conditionalget.rb:25:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/head.rb:14:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/flash.rb:242:in `call'
rack (1.4.5) lib/rack/session/abstract/id.rb:210:in `context'
rack (1.4.5) lib/rack/session/abstract/id.rb:205:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/cookies.rb:338:in `call'
activerecord (3.2.2) lib/active_record/query_cache.rb:64:in `call'
activerecord (3.2.2) lib/active_record/connection_adapters/abstract/connection_pool.rb:443:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `_run__823762421__call__1059391116__callbacks'
activesupport (3.2.2) lib/active_support/callbacks.rb:405:in `__run_callback'
activesupport (3.2.2) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
activesupport (3.2.2) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (3.2.2) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/reloader.rb:65:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
railties (3.2.2) lib/rails/rack/logger.rb:26:in `call_app'
railties (3.2.2) lib/rails/rack/logger.rb:16:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/request_id.rb:22:in `call'
rack (1.4.5) lib/rack/methodoverride.rb:21:in `call'
rack (1.4.5) lib/rack/runtime.rb:17:in `call'
activesupport (3.2.2) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
rack (1.4.5) lib/rack/lock.rb:15:in `call'
actionpack (3.2.2) lib/action_dispatch/middleware/static.rb:61:in `call'
railties (3.2.2) lib/rails/engine.rb:479:in `call'
railties (3.2.2) lib/rails/application.rb:220:in `call'
rack (1.4.5) lib/rack/content_length.rb:14:in `call'
railties (3.2.2) lib/rails/rack/log_tailer.rb:14:in `call'
unicorn (4.3.0) lib/unicorn/http_server.rb:530:in `process_client'
unicorn (4.3.0) lib/unicorn/http_server.rb:605:in `worker_loop'
unicorn (4.3.0) lib/unicorn/http_server.rb:487:in `spawn_missing_workers'
unicorn (4.3.0) lib/unicorn/http_server.rb:137:in `start'
unicorn-rails (1.0.0) lib/unicorn/rails.rb:20:in `run'
rack (1.4.5) lib/rack/server.rb:268:in `start'
railties (3.2.2) lib/rails/commands/server.rb:70:in `start'
railties (3.2.2) lib/rails/commands.rb:55:in `block in <top (required)>'
railties (3.2.2) lib/rails/commands.rb:50:in `tap'
railties (3.2.2) lib/rails/commands.rb:50:in `<top (required)>'
script/rails:6:in `require'
script/rails:6:in `<main>
Heroku 日志：
2013-08-14T10:26:26.778316+00:00 app[web.1]: Started GET "/users/B9sqVDkfpBjwDx1ZH7sR/activate" for 106.51.119.186 at 2013-08-14 10:26:26 +0000
2013-08-14T10:26:29.052364+00:00 app[web.1]: ActiveRecord::RecordNotSaved (ActiveRecord::RecordNotSaved):
2013-08-14T10:26:29.052364+00:00 app[web.1]:
2013-08-14T10:26:29.052364+00:00 app[web.1]:
2013-08-14T10:26:29.052364+00:00 app[web.1]: app/controllers/users_controller.rb:33:in `activate'