I'm using Redmine 2.0-stable (from github) on ubuntu server 12.04 with the following environment:
About your application's environment
Ruby version 1.9.3 (x86_64-linux)
RubyGems version 1.8.11
Rack version 1.4
Rails version 3.2.6
Active Record version 3.2.6
Action Pack version 3.2.6
Active Resource version 3.2.6
Action Mailer version 3.2.6
Active Support version 3.2.6
Middleware Rack::Cache, ActionDispatch::Static, Rack::Lock, #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x000000027f8d50>, Rack::Runtime, Rack::MethodOverride, ActionDispatch::RequestId, Rails::Rack::Logger, ActionDispatch::ShowExceptions, ActionDispatch::DebugExceptions, ActionDispatch::RemoteIp, ActionDispatch::Callbacks, ActiveRecord::ConnectionAdapters::ConnectionManagement, ActiveRecord::QueryCache, ActionDispatch::Cookies, ActionDispatch::Session::CookieStore, ActionDispatch::Flash, ActionDispatch::ParamsParser, ActionDispatch::Head, Rack::ConditionalGet, Rack::ETag, ActionDispatch::BestStandardsSupport, OpenIdAuthentication
Application root /opt/redmine
Environment production
Database adapter mysql2
Database schema version 20120422150750