ruby on rails - Undefined method `year' for nil:NilClass -

i'm using monologue engine creata blog. follow readme file @ https://github.com/jipiboily/monologue config app , database.

when try create new article using monologue interface error: undefined method 'year' nil:nilclass.

someone know how fix it?

complete log file:

nomethoderror (undefined method `year' nil:nilclass): activesupport (4.1.1) lib/active_support/values/time_zone.rb:290:in `parse' activesupport (4.1.1) lib/active_support/core_ext/string/zones.rb:9:in `in_time_zone' activerecord (4.1.1) lib/active_record/attribute_methods/time_zone_conversion.rb:37:in `published_at=' activerecord (4.1.1) lib/active_record/attribute_assignment.rb:45:in `public_send' activerecord (4.1.1) lib/active_record/attribute_assignment.rb:45:in `_assign_attribute' activerecord (4.1.1) lib/active_record/attribute_assignment.rb:32:in `block in assign_attributes' activerecord (4.1.1) lib/active_record/attribute_assignment.rb:26:in `each' activerecord (4.1.1) lib/active_record/attribute_assignment.rb:26:in `assign_attributes' activerecord (4.1.1) lib/active_record/core.rb:452:in `init_attributes' activerecord (4.1.1) lib/active_record/core.rb:198:in `initialize' activerecord (4.1.1) lib/active_record/inheritance.rb:30:in `new' activerecord (4.1.1) lib/active_record/inheritance.rb:30:in `new' monologue (0.4.1) app/controllers/monologue/admin/posts_controller.rb:24:in `create' actionpack (4.1.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action' actionpack (4.1.1) lib/abstract_controller/base.rb:189:in `process_action' actionpack (4.1.1) lib/action_controller/metal/rendering.rb:10:in `process_action' actionpack (4.1.1) lib/abstract_controller/callbacks.rb:20:in `block in process_action' activesupport (4.1.1) lib/active_support/callbacks.rb:113:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:113:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:149:in `block in halting_and_conditional' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:229:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:229:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:229:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:229:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:166:in `block in halting' activesupport (4.1.1) lib/active_support/callbacks.rb:86:in `call' activesupport (4.1.1) lib/active_support/callbacks.rb:86:in `run_callbacks' actionpack (4.1.1) lib/abstract_controller/callbacks.rb:19:in `process_action' actionpack (4.1.1) lib/action_controller/metal/rescue.rb:29:in `process_action' actionpack (4.1.1) lib/action_controller/metal/instrumentation.rb:31:in `block in process_action' activesupport (4.1.1) lib/active_support/notifications.rb:159:in `block in instrument' activesupport (4.1.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument' activesupport (4.1.1) lib/active_support/notifications.rb:159:in `instrument' actionpack (4.1.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action' actionpack (4.1.1) lib/action_controller/metal/params_wrapper.rb:250:in `process_action' activerecord (4.1.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action' actionpack (4.1.1) lib/abstract_controller/base.rb:136:in `process' actionview (4.1.1) lib/action_view/rendering.rb:30:in `process' actionpack (4.1.1) lib/action_controller/metal.rb:195:in `dispatch' actionpack (4.1.1) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch' actionpack (4.1.1) lib/action_controller/metal.rb:231:in `block in action' actionpack (4.1.1) lib/action_dispatch/routing/route_set.rb:80:in `call' actionpack (4.1.1) lib/action_dispatch/routing/route_set.rb:80:in `dispatch' actionpack (4.1.1) lib/action_dispatch/routing/route_set.rb:48:in `call' actionpack (4.1.1) lib/action_dispatch/journey/router.rb:71:in `block in call' actionpack (4.1.1) lib/action_dispatch/journey/router.rb:59:in `each' actionpack (4.1.1) lib/action_dispatch/journey/router.rb:59:in `call' actionpack (4.1.1) lib/action_dispatch/routing/route_set.rb:676:in `call' railties (4.1.1) lib/rails/engine.rb:514:in `call' railties (4.1.1) lib/rails/railtie.rb:194:in `public_send' railties (4.1.1) lib/rails/railtie.rb:194:in `method_missing' actionpack (4.1.1) lib/action_dispatch/journey/router.rb:71:in `block in call' actionpack (4.1.1) lib/action_dispatch/journey/router.rb:59:in `each' actionpack (4.1.1) lib/action_dispatch/journey/router.rb:59:in `call' actionpack (4.1.1) lib/action_dispatch/routing/route_set.rb:676:in `call' rack (1.5.4) lib/rack/etag.rb:23:in `call' rack (1.5.4) lib/rack/conditionalget.rb:35:in `call' rack (1.5.4) lib/rack/head.rb:11:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/params_parser.rb:27:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/flash.rb:254:in `call' rack (1.5.4) lib/rack/session/abstract/id.rb:225:in `context' rack (1.5.4) lib/rack/session/abstract/id.rb:220:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/cookies.rb:560:in `call' activerecord (4.1.1) lib/active_record/query_cache.rb:36:in `call' activerecord (4.1.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:621:in `call' activerecord (4.1.1) lib/active_record/migration.rb:380:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call' activesupport (4.1.1) lib/active_support/callbacks.rb:82:in `run_callbacks' actionpack (4.1.1) lib/action_dispatch/middleware/callbacks.rb:27:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/reloader.rb:73:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/remote_ip.rb:76:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call' railties (4.1.1) lib/rails/rack/logger.rb:38:in `call_app' railties (4.1.1) lib/rails/rack/logger.rb:20:in `block in call' activesupport (4.1.1) lib/active_support/tagged_logging.rb:68:in `block in tagged' activesupport (4.1.1) lib/active_support/tagged_logging.rb:26:in `tagged' activesupport (4.1.1) lib/active_support/tagged_logging.rb:68:in `tagged' railties (4.1.1) lib/rails/rack/logger.rb:20:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/request_id.rb:21:in `call' rack (1.5.4) lib/rack/methodoverride.rb:21:in `call' rack (1.5.4) lib/rack/runtime.rb:17:in `call' activesupport (4.1.1) lib/active_support/cache/strategy/local_cache_middleware.rb:26:in `call' rack (1.5.4) lib/rack/lock.rb:17:in `call' actionpack (4.1.1) lib/action_dispatch/middleware/static.rb:64:in `call' rack (1.5.4) lib/rack/sendfile.rb:112:in `call' railties (4.1.1) lib/rails/engine.rb:514:in `call' railties (4.1.1) lib/rails/application.rb:144:in `call' rack (1.5.4) lib/rack/lock.rb:17:in `call' rack (1.5.4) lib/rack/content_length.rb:14:in `call' rack (1.5.4) lib/rack/handler/webrick.rb:60:in `service' /usr/local/lib/ruby/2.2.0/webrick/httpserver.rb:138:in `service' /usr/local/lib/ruby/2.2.0/webrick/httpserver.rb:94:in `run' /usr/local/lib/ruby/2.2.0/webrick/server.rb:294:in `block in start_thread' 

i resolved using ruby 2.1.2.

thanks all!