调用方法“.create”时，我的项目中的所有模型都出现以下错误：
NoMethodError: undefined method `[]' for nil:NilClass
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/attribute_methods/read.rb:86:in `block in read_attribute'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/attribute_methods/read.rb:84:in `fetch'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/attribute_methods/read.rb:84:in `read_attribute'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/attribute_methods/primary_key.rb:19:in `id'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/transactions.rb:341:in `remember_transaction_record_state'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/transactions.rb:280:in `rollback_active_record_state!'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/activerecord/lib/active_record/transactions.rb:269:in `save'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/gems/protected_attributes-1.0.3/lib/active_record/mass_assignment_security/persistence.rb:46:in `create'
from (irb):1
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/railties/lib/rails/commands/console.rb:90:in `start'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/railties/lib/rails/commands/console.rb:9:in `start'
from /home/pavelkhrulev/.rvm/gems/ruby-2.0.0-p195@spasibo/bundler/gems/rails-b52b0bebd147/railties/lib/rails/commands.rb:62:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
以前一切正常，但我做了捆绑更新，现在不行了。我的宝石文件：
ruby '2.0.0'
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', git: 'https://github.com/rails/rails.git', branch: '4-0-stable'
# Use sqlite3 as the database for Active Record
#gem 'sqlite3'
gem 'pg'
# Use SCSS for stylesheets
gem 'sass-rails', git: 'https://github.com/rails/sass-rails.git'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', git: 'git://github.com/rails/coffee-rails.git'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
group :production do
gem 'therubyracer', platforms: :ruby
end
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
gem 'jquery-turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 1.2'
group :doc do
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', require: false
end
# Use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# Use unicorn as the app server
gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano', group: :development
# Use debugger
# gem 'debugger', group: [:development, :test]
# Use heroku gem to make all features enabled
gem 'rails_12factor', group: :production
# New Relic perfomance monitor
gem 'newrelic_rpm'
# Application gems
gem "devise", :git => "http://github.com/plataformatec/devise.git"
gem 'protected_attributes'
gem 'russian'
gem 'devise-russian'
gem 'kaminari'
# Admin panel
gem 'activeadmin', github: 'gregbell/active_admin', branch: 'rails4'
gem 'ransack'
gem 'inherited_resources', github: 'josevalim/inherited_resources'
gem 'formtastic', github: 'justinfrench/formtastic'
我查看了源代码，使用了谷歌搜索，但仍然不知道如何解决这个问题。我将不胜感激。我真的坚持了下来。我需要交付几乎完成的项目。