Ruby (Rack) application could not be started

http://127.0.0.1 ==> Ruby (Rack) application could not be started, Can someone help?

A source file that the application requires, is missing.

*
  It is possible that you didn't upload your application files correctly. Please check whether all your application files are uploaded.
*
  A required library may not installed. Please install all libraries that this application requires.

Further information about the error may have been written to the application's log file. Please check it in order to analyse the problem.

Error message:
    no such file to load -- bundler
Exception class:
    LoadError
Application root:
    /var/www/project
Backtrace:
    #   File    Line    Location
    0   /home/user1/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb     36  in `require'
    1   /home/user1/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb     36  in `require'
    2   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/utils.rb   325     in `prepare_app_process'
    3   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb    155     in `block in initialize_server'
    4   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/utils.rb   572     in `report_app_init_status'
    5   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb    153     in `initialize_server'
    6   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb     204     in `start_synchronously'
    7   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb     180     in `start'
    8   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb    128     in `start'
    9   /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb   253     in `block (2 levels) in spawn_rack_application'
    10  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb  132     in `lookup_or_add'
    11  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb   246     in `block in spawn_rack_application'
    12  /hom开发者_开发百科e/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb  82  in `block in synchronize'
    13      prelude>    10:in `synchronize'
    14  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb  79  in `synchronize'
    15  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb   244     in `spawn_rack_application'
    16  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb   137     in `spawn_application'
    17  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb   275     in `handle_spawn_application'
    18  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb     357     in `server_main_loop'
    19  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb     206     in `start_synchronously'
    20  /home/user1/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/helper-scripts/passenger-spawn-server    99  in `'

---

gem install bundler should do the trick here. "Error message: no such file to load -- bundler" is the relevant line. You'll probably need to run bundle install after installing the bundler gem as well.