Deploy Ruby project on Ubuntu 18.0

Hi,
I am referring the doc "https://gorails.com/deploy/ubuntu/18.04#nginx" for deploy the project.
After running the command "cap install STAGES=production"
I got error list :
LoadError: cannot load such file -- /usr/lib/ruby/vendor_ruby/Capfile
/usr/lib/ruby/vendor_ruby/rake/rake_module.rb:29:in load'
/usr/lib/ruby/vendor_ruby/rake/rake_module.rb:29:inload_rakefile'
/usr/lib/ruby/vendor_ruby/rake/application.rb:703:in raw_load_rakefile'
/usr/lib/ruby/vendor_ruby/rake/application.rb:104:inblock in load_rakefile'
/usr/lib/ruby/vendor_ruby/rake/application.rb:186:in standard_exception_handling'
/usr/lib/ruby/vendor_ruby/rake/application.rb:103:inload_rakefile'
/usr/lib/ruby/vendor_ruby/rake/application.rb:82:in block in run'
/usr/lib/ruby/vendor_ruby/rake/application.rb:186:instandard_exception_handling'
/usr/lib/ruby/vendor_ruby/rake/application.rb:80:in run'
/usr/lib/ruby/vendor_ruby/capistrano/application.rb:14:inrun'
/usr/bin/cap:3:in `

Please help me to resolve this issue asap as its urgent to deploy.

Now this above cap file problem has been resolved with the below commands:
group :development do
gem "capistrano", "~> 3.14", require: false ---> make it false
end

$ bundle install

$ bundle exec cap install

and after that edit all the capfiles as per the " "https://gorails.com/deploy/ubuntu/18.04#nginx" "
Application not deployed.

Please help me to troubleshoot .