Redmine

Hi everyone!
I have a problem with my redmine installations. I've just upgraded ruby on my debian and redmine finally stopped working. After hours of "applying fixes" to ruby installation and moving to rvm I'm stuck on problem show below. Please, help :)

I'm using redmine from 2.5-stable@13176.
I've installed ruby through rvm using this guide: http://martin-denizet.com/install-redmine-2-5-x-with-git-and-subversion-on-debian-with-apache2-rvm-and-passenger/

# ruby script/rails server webrick -e production
=> Booting WEBrick
=> Rails 3.2.18 application starting in production on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Storing outgoing emails configuration in config/email.yml is deprecated. You should now store it in config/configuration.yml using the email_delivery setting.
[2014-06-09 00:41:22] INFO  WEBrick 1.3.1
[2014-06-09 00:41:22] INFO  ruby 2.0.0 (2014-05-08) [x86_64-linux]
[2014-06-09 00:41:22] INFO  WEBrick::HTTPServer#start: pid=21533 port=3000
Started GET "/" for 95.49.xxx.xxx at 2014-06-09 00:41:24 +0200
Processing by WelcomeController#index as HTML
   (0.2ms)  SELECT MAX(`settings`.`updated_on`) AS max_id FROM `settings`
Completed 500 Internal Server Error in 8.8ms

NameError (uninitialized constant Arel::Relation):
  app/models/setting.rb:245:in `find_or_default'
  app/models/setting.rb:110:in `[]'
  app/models/setting.rb:143:in `autologin?'
  app/controllers/application_controller.rb:152:in `try_to_autologin'
  app/controllers/application_controller.rb:112:in `find_current_user'
  app/controllers/application_controller.rb:100:in `user_setup'

Currently i have installed following gems:

# gem list

*** LOCAL GEMS ***

actionmailer (3.2.18)
actionpack (3.2.18)
activemodel (3.2.18)
activerecord (3.2.18)
activeresource (3.2.18)
activesupport (3.2.18)
arel (4.0.2)
awesome_nested_set (2.1.6)
bigdecimal (1.2.0)
builder (3.0.0)
bundler (1.6.2)
bundler-unload (1.0.2)
coderay (1.1.0)
erubis (2.7.0)
executable-hooks (1.3.2)
gem-wrappers (1.2.4)
hike (1.2.3)
i18n (0.6.9)
io-console (0.4.2)
journey (1.0.4)
jquery-rails (2.0.3)
json (1.8.1, 1.7.7)
mail (2.5.4)
mime-types (1.25.1)
minitest (4.3.2)
multi_json (1.10.1)
mysql2 (0.3.16)
net-ldap (0.3.1)
polyglot (0.3.5)
psych (2.0.0)
rack (1.4.5)
rack-cache (1.2)
rack-openid (1.4.2)
rack-ssl (1.3.4)
rack-test (0.6.2)
rails (3.2.18)
railties (3.2.18)
rake (10.1.1, 0.9.6)
rdoc (4.1.1, 4.0.0)
redcarpet (2.3.0)
rmagick (2.13.2)
ruby-openid (2.3.0)
rubygems-bundler (1.4.4)
rvm (1.11.3.9)
sprockets (2.12.1)
test-unit (2.0.0.0)
thor (0.19.1)
thread_safe (0.3.4)
tilt (1.4.1)
treetop (1.4.15)
tzinfo (1.2.1)