Redmine

If I execute "gem update", psych will be update to v2.0.6, and there have some error:

superclass mismatch for class Mark (TypeError)
  /usr/local/lib/ruby/2.1.0/psych/parser.rb:33:in `<class:Parser>'
  /usr/local/lib/ruby/2.1.0/psych/parser.rb:32:in `<module:Psych>'
  /usr/local/lib/ruby/2.1.0/psych/parser.rb:1:in `<top (required)>'
  /usr/local/lib/ruby/2.1.0/psych.rb:7:in `require'
  /usr/local/lib/ruby/2.1.0/psych.rb:7:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/activesupport-3.2.19/lib/active_support/ordered_hash.rb:2:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/activesupport-3.2.19/lib/active_support/ordered_hash.rb:2:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/activesupport-3.2.19/lib/active_support/ordered_options.rb:1:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/activesupport-3.2.19/lib/active_support/ordered_options.rb:1:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/configuration.rb:2:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/configuration.rb:2:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/railtie.rb:2:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/railtie.rb:2:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/engine.rb:1:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/engine.rb:1:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/plugin.rb:1:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/plugin.rb:1:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/application.rb:3:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/application.rb:3:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails.rb:10:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails.rb:10:in `<top (required)>'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/all.rb:1:in `require'
  /usr/local/lib/ruby/gems/2.1.0/gems/railties-3.2.19/lib/rails/all.rb:1:in `<top (required)>'
  /home/www/redmine-2.5.2/config/application.rb:3:in `require'
  /home/www/redmine-2.5.2/config/application.rb:3:in `<top (required)>'
  /home/www/redmine-2.5.2/config/environment.rb:2:in `require'
  /home/www/redmine-2.5.2/config/environment.rb:2:in `<top (required)>'
  config.ru:3:in `require'
  config.ru:3:in `block in <main>'
  /usr/local/lib/ruby/gems/2.1.0/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
  /usr/local/lib/ruby/gems/2.1.0/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
  config.ru:1:in `new'
  config.ru:1:in `<main>'
  /usr/local/passenger-4.0.50/helper-scripts/rack-preloader.rb:112:in `eval'
  /usr/local/passenger-4.0.50/helper-scripts/rack-preloader.rb:112:in `preload_app'
  /usr/local/passenger-4.0.50/helper-scripts/rack-preloader.rb:158:in `<module:App>'
  /usr/local/passenger-4.0.50/helper-scripts/rack-preloader.rb:29:in `<module:PhusionPassenger>'
  /usr/local/passenger-4.0.50/helper-scripts/rack-preloader.rb:28:in `<main>'

So if I uninstall psych v2.0.6 and use v2.0.5, everything is OK.