title: Rails 5.2 encrypted credentials not saving
body: <p>When I do <code>bin/rails credentials:edit</code> my editor opens a file like <code>credentials.yml.enc.1234</code> with default content. After I'm done editing, I hit save, and the console reads <code>New credentials encrypted and saved.</code> </p>
  
  <p>After I run <code>bin/rails credentials:edit</code> again, another temp file gets opened (<code>credentials.yml.enc.4321</code>) and the contents are back to default. </p>
  
  <p>How can I make the credentials persist?</p>