Apache-Passenger can't start my production rails application - ruby-on-rails

Question

I'm new to deploying rails applications and for what I read in many sites the Apache/Passenger combo was one of the simplest ones; however I have encountered that Passenger does not want to start my application and displays the following error message when entering the sudo tail -50 /var/log/apache2/error.log
command:
Could not spawn process for application /home/test/Documents/sites/depot:
An error occured while starting up the preloader.
Message from application: cannot load such file -- bundler/setup (LoadError)
/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:53:in `require'
/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:53:in `require'
/usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:406:in
`activate_gem'
...
age/Cor/Req/CheckoutSession.cpp:252 ]: [Client 1-1] Cannot checkout session
because a spawning error occurred. The identifier of the error is 6ce15bbe.
Please see earlier logs for details about the error.
I suspect it has to do with my ruby installation, I used rbenv and got the 2.2.3 version but in the error message it was linking to a 2.0.0 version which I have never installed.
I also suspect that it has something to do with me using this two commands from another guide:
sudo rm /usr/bin/ruby
sudo ln -s /usr/local/bin/ruby /usr/bin/ruby
https://www.digitalocean.com/community/tutorials/how-to-deploy-a-rails-app-with-passenger-and-apache-on-ubuntu-14-04
If anybody know how to fix this headache of a problem I'll really appreciate it.
Thanks!

Answer 1

You probably need to specify correct PassengerDefaultRuby in your httpd.conf file.
My recommendation is to go through the installation of passenger using their official guide:
https://www.phusionpassenger.com/library/install/apache/

Answer 2

After some clues left by #dimakura and #CamdenNarzt I was able to solve this in two stages.
As I suspected Passenger was using the wrong version of ruby, to fix this I modified the passenger.conf file located under /etc/apache2/mods-available/ with the output of the which ruby command:
Added the line (replace with your own which ruby output)
PassengerRuby /home/test/.rbenv/shims/ruby
Restarted apache got a "Incomplete response received from application" error message, checked the logs and noticed that the proper version of ruby was now being used but got an error message:
"Missing secret_token and secret_key_base for 'production' environment, set these values in config/secrets.yml"
Installed the Figaro gem by following the instructions on this site: https://www.twilio.com/blog/2015/02/managing-development-environment-variables-across-multiple-ruby-applications.html then generated a secret key using the command:
rake secret
Copied the output and opened the config/application.yml file where I entered:
SECRET_KEY_BASE: [output key from rake secret command]
Restarted Apache and it worked!!