my config/deploy.rb

deploy.rb

lock '3.10.2'

set :application, 'APP_NAME'
set :repo_url, 'REPO_URI'
set :linked_dirs, %w(log tmp/pids tmp/cache tmp/sockets bundle) # public は微妙なので場合に応じて

set :rbenv_type, :user # :system(/usr/local/rbenv) or :user(~/.rbenv)
set :rbenv_ruby, '2.5.1'
set :linked_files, ['config/master.key']

after 'deploy:publishing', 'deploy:restart'
namespace :deploy do
  desc 'Restart application'
  task :restart do
    invoke 'unicorn:restart'
  end
end