title: Customize a third party gem and use it in production
body: <p>I am using a gem that I customized for my app (using Rails 5.0). I modified just a few lines of code to get it to do what I need and it works fine in my local environment. But how do I change the gem code in production? There is the vendor directory in Rails projects and a 5+ year old SO advice was to put it in the no longer existing vendor/gems directory. Should I put it in the vendor directory? Make a vendor/gems directory and put it there? And if I do how do I tell Rails to look there?</p>
  
  <p>Changing the official gem itself is something I may try to do as well but in the short term I just want to make sure I can use the customized gem in production. </p>