Capistrano Production Deploy -> rbenv - ruby-on-rails

Question

I think I have set up Capistrano3 correctly on my machine and that it should be connecting to my server. When I run cap production deploy (on my machine) I receive the following error messenger:
DEBUG [2959f403] Running /usr/bin/env [ -d ~/.rbenv/versions/2.1.2 ] as [user#myIP]
DEBUG [2959f403] Command: [ -d ~/.rbenv/versions/2.1.2 ]
DEBUG [2959f403] Finished in 0.420 seconds with exit status 1 (failed).
ERROR rbenv: 2.1.2 is not installed or not found in ~/.rbenv/versions/2.1.2
(Backtrace restricted to imported tasks)
cap aborted!
SSHKit::Runner::ExecuteError: Exception while executing as [user#myIP]: exit
SystemExit: exit
Tasks: TOP => rbenv:validate
(See full trace by running task with --trace)
On my machine (iMac):
$ ruby -v
ruby 2.1.2p95
$ rbenv -v
rbenv 0.4.0
$ which rebind
/usr/local/bin/rbenv
On my server (ubuntu)
$ ruby -v
ruby 2.1.2p95
$ rbenv -v
rbenv 0.4.0-151-g83ac0fb
$ which rebind
/home/[user]/.rbenv/bin/rbenv
Any ideas how to fix this?
** More Info From Comments **
deploy.rb
# config valid only for current version of Capistrano
lock '3.4.0'
set :application, [app name]
set :repo_url, [repo location]
set :repository, [repo location]
set :scm, :git
set :deploy_user, [user]
set :user, [user]
set :use_sudo, false
set :rails_env, "production"
set :deploy_via, :copy
# setup rvm.
# how many old releases do we want to keep
set :keep_releases, 5
# files we want symlinking to specific entries in shared.
set :linked_files, %w{config/database.yml config/application.yml}
# dirs we want symlinking to shared
set :linked_dirs, %w{bin log tmp/pids tmp/cache tmp/sockets vendor/bundle public/system}
# what specs should be run before deployment is allowed to
# continue, see lib/capistrano/tasks/run_tests.cap
set :tests, []
# which config files should be copied by deploy:setup_config
# see documentation in lib/capistrano/tasks/setup_config.cap
# for details of operations
set(:config_files, %w(
nginx.conf
database.example.yml
log_rotation
monit
unicorn.rb
unicorn_init.sh
))
# which config files should be made executable after copying
# by deploy:setup_config
set(:executable_config_files, %w(
unicorn_init.sh
))
# files which need to be symlinked to other parts of the
# filesystem. For example nginx virtualhosts, log rotation
# init scripts etc.
set(:symlinks, [
{
source: "nginx.conf",
link: "/etc/nginx/sites-enabled/#{fetch(:full_app_name)}"
},
{
source: "unicorn_init.sh",
link: "/etc/init.d/unicorn_#{fetch(:full_app_name)}"
},
{
source: "log_rotation",
link: "/etc/logrotate.d/#{fetch(:full_app_name)}"
},
{
source: "monit",
link: "/etc/monit/conf.d/#{fetch(:full_app_name)}.conf"
}
])
namespace :deploy do
# make sure we're deploying what we think we're deploying
before :deploy, "deploy:check_revision"
# only allow a deploy with passing tests to deployed
before :deploy, "deploy:run_tests"
# compile assets locally then rsync
after :finishing, 'deploy:cleanup'
after 'deploy:publishing', 'deploy:restart'
end
Server
$ ls /home/[user]/.rbenv/versions/
[blank... ]
$

Answer 1

If /home/[user]/.rbenv/versions is an empty directory on the server, then you have no versions of ruby installed.
Try running rbenv install 2.1.2 on the server. You may need to install the ruby-build plugin first.