Quick reference on installing specific versions of rails on an “older” version of ubuntu without the need of having all packages in the ubuntu repositories.

\curl -L https://get.rvm.io | bash -s stable --ruby
/usr/local/rvm/bin/gem install ... (all needed gems)
/usr/local/rvm/bin/gem install passenger
apt-get install libcurl4-openssl-dev apache2-threaded-dev
/usr/local/rvm/gems/ruby-2.0.0-p247/gems/passenger-4.0.10/bin/passenger-install-apache2-module

The Apache 2 module was successfully installed.

Please edit your Apache configuration file, and add these lines:

   LoadModule passenger_module /usr/local/rvm/gems/ruby-2.0.0-p247/gems/passenger-4.0.10/buildout/apache2/mod_passenger.so
   PassengerRoot /usr/local/rvm/gems/ruby-2.0.0-p247/gems/passenger-4.0.10
   PassengerDefaultRuby /usr/bin/ruby1.8

After you restart Apache, you are ready to deploy any number of Ruby on Rails
applications on Apache, without any further Ruby on Rails-specific
configuration!

After doing so, you can continue to install redmine as described in http://www.redmine.org/projects/redmine/wiki/RedmineInstall

/usr/local/rvm/gems/ruby-2.0.0-p247/bin/bundle install --without development test

This will fail if the environment is not set correctly – this helped me a lot:
http://stackoverflow.com/questions/12127603/usr-bin-env-ruby-noexec-wrapper-fails-with-no-file-or-directory

source /usr/local/rvm/environments/ruby-2.0.0-p247

And finally the last missing gem:

/usr/local/rvm/bin/gem install rake -v=10.1.0

That’s it.