title: How to start rails server in production mode using unicorn and config file?
body: <p>I add <code>Gem 'unicorn'</code> to Gemfile and call <code>rails server unicorn -e production</code>, but I get a load error. Then I add <code>Gem 'unicorn_rails'</code>, then call <code>rails server unicorn -e production</code>, but I can't find the socket file. So I am considering if it doesn't use the <code>config/unicorn.rb</code> file as the configuration? So I call <code>unicorn_rails -c config/unicorn.rb -E production -D</code>, but I get another error <code>text file busy</code>.</p>
  
  <p>So now I am stuck in this matter, could you help me? :)</p>