Capistrano Deployment error fixed while deployment on Digital Ocean :

gem 'capistrano', '~> 3.4.0'
gem 'capistrano-bundler', '~> 1.1.2'
gem 'capistrano-rails', '~> 1.1.1'

config/deploy.rb : lock '3.4.1'

cap production deploy

error: 
cd /home/ubuntu/Trusttd/releases/20160802102011 && /usr/local/rvm/bin/rvm default do bundle install --path /home/ubuntu/Trusttd/shared/bundle --without development test --deployment --quiet
/usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:149:in ``': Cannot allocate memory - git (Errno::ENOMEM)
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:149:in `block in git'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/shared_helpers.rb:72:in `call'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/shared_helpers.rb:72:in `with_clean_git_env'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:149:in `git'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:83:in `version'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/env.rb:78:in `git_version'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/env.rb:22:in `report'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:74:in `request_issue_report_for'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:40:in `log_error'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:100:in `rescue in with_friendly_errors'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:98:in `with_friendly_errors'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/exe/bundle:19:in `<top (required)>'
from /usr/local/rvm/gems/ruby-2.2.3/bin/bundle:23:in `load'
from /usr/local/rvm/gems/ruby-2.2.3/bin/bundle:23:in `<main>'
from /usr/local/rvm/gems/ruby-2.2.3/bin/ruby_executable_hooks:15:in `eval'
from /usr/local/rvm/gems/ruby-2.2.3/bin/ruby_executable_hooks:15:in `<main>'
(Backtrace restricted to imported tasks)
cap aborted!
SSHKit::Runner::ExecuteError: Exception while executing as root@128.199.198.27: bundle exit status: 1
bundle stdout: Nothing written
bundle stderr: /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:149:in ``': Cannot allocate memory - git (Errno::ENOMEM)
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:149:in `block in git'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/shared_helpers.rb:72:in `call'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/shared_helpers.rb:72:in `with_clean_git_env'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:149:in `git'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/source/git/git_proxy.rb:83:in `version'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/env.rb:78:in `git_version'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/env.rb:22:in `report'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:74:in `request_issue_report_for'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:40:in `log_error'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:100:in `rescue in with_friendly_errors'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/lib/bundler/friendly_errors.rb:98:in `with_friendly_errors'
from /usr/local/rvm/gems/ruby-2.2.3/gems/bundler-1.12.5/exe/bundle:19:in `<top (required)>'
from /usr/local/rvm/gems/ruby-2.2.3/bin/bundle:23:in `load'
from /usr/local/rvm/gems/ruby-2.2.3/bin/bundle:23:in `<main>'
from /usr/local/rvm/gems/ruby-2.2.3/bin/ruby_executable_hooks:15:in `eval'
from /usr/local/rvm/gems/ruby-2.2.3/bin/ruby_executable_hooks:15:in `<main>'

Assign permission for your releases folder after ssh login

sudo chmod -R 777 /home/ubuntu/******/releases/

root@*****:~# cd /home/ubuntu/******/current/

gem install sqlite3 -v '1.3.10

gem install nokogiri 

gem install ransack

then again try

cap production deploy

Cheers,

Hemant