title: Upgrading Rails: What am I to do with new_framework_defaults file?
body: <p>I am upgrading from rails 5.1 to 5.2.
  I did <code>bundle update rails</code> (plus some dependencies) and <code>rails app:update</code>.
  Now i have the file <code>initializers/new_framework_defaults_5_2.rb</code>, with all lines are commented out. </p>
  
  <p>I am not sure what I need to do now. My app works normally, so I guess, with all lines are commented out I am already on all new defaults. Then I do not need that file, right?</p>
  
  <p>Suppose I run into errors, the values set in the files are the new defaults? So I would uncomment, maybe flip the boolean and try to find out what caused the error?</p>
  
  <p>thank you for your help</p>