Redmine

Hi, I've installed Redmine in the past a few times. But for this time I'm not able to finish it off. Probably someone could help me?

I've Redmine installed under /var/www/redmine on my Debian 8 host with the help of an (pretty) old tutorial on the installation of Redmine under Apache with Passenger. I now get an errormessage from Passenger saying:

cannot load such file -- bundler/setup (LoadError)
  /usr/local/rvm/rubies/ruby-2.4.1/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
  /usr/local/rvm/rubies/ruby-2.4.1/lib/ruby/site_ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
  /usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:263:in `block in run_load_path_setup_code'
  /usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:366:in `running_bundler'
  /usr/lib/ruby/vendor_ruby/phusion_passenger/loader_shared_helpers.rb:261:in `run_load_path_setup_code'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:100:in `preload_app'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:158:in `<module:App>'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:29:in `<module:PhusionPassenger>'
  /usr/share/passenger/helper-scripts/rack-preloader.rb:28:in `<main>'

It also says, it's using "/usr/bin/ruby2.4.1" under "Ruby interpreter command"
And here's the Envoirement Variables

APACHE_RUN_DIR = /var/run/apache2
APACHE_PID_FILE = /var/run/apache2/apache2.pid
PATH = /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
APACHE_LOCK_DIR = /var/lock/apache2
LANG = C
APACHE_RUN_USER = www-data
APACHE_RUN_GROUP = www-data
APACHE_LOG_DIR = /var/log/apache2
PWD = /var/www/redmine
PASSENGER_DEBUG_DIR = /tmp/passenger.spawn-debug.XXXXyUQkZR
USER = www-data
LOGNAME = www-data
SHELL = /usr/sbin/nologin
HOME = /var/www
IN_PASSENGER = 1
PYTHONUNBUFFERED = 1
NODE_PATH = /usr/share/passenger/node
RAILS_ENV = production
RACK_ENV = production
WSGI_ENV = production
NODE_ENV = production
PASSENGER_APP_ENV = production
SERVER_PROTOCOL = HTTP/1.1
SERVER_SOFTWARE = Apache/2.4.10 (Debian)
DOCUMENT_ROOT = /var/www/redmine/public
SERVER_ADMIN = webmaster@localhost
QUERY_STRING = 
SERVER_NAME = localhost
REMOTE_PORT = 52824
REMOTE_ADDR = 10.0.0.2
SERVER_PORT = 80
REQUEST_METHOD = GET
SERVER_ADDR = 10.0.50.5
REQUEST_URI = /

@edit
I'm Running Rails 4.2.8, mysql Ver 14.14 Distrib 5.5.58 and I think I'm using Webrick, but I'm not sure.

@edit I can run Redmine with the following command and can manage Redmine on localhost on port 30:

bundle exec rails server webrick -e production

If I need to post some more of that error message just write back and I will reply.
Hope, someone can help me getting Redmine up and running :)

Thanks, Manuel