Running Foreman with Unicorn

Hi, I've tried to build passenger free environment so ran puppet + unicorn

  • nginx
    When trying to run Foreman with Unicorn i received You have already
    activated rack 1.5.2, but your Gemfile requires rack 1.2.8
    after downgrading the rack i recieved
    /usr/share/foreman/vendor/ruby/1.8/gems/activerecord-3.0.20/lib/active_record/connection_adapters/abstract/connection_specification.rb:62:in
    `establish_connection': development database is not configured
    (ActiveRecord::AdapterNotSpecified)

exported environment and it ran ok.
So i can export variables in startup script.

but how to manage rack downgrade ?
I would not like to ran it with outdated version.

Any ideas?