What is the "Rails Way" to re-associate posts or other objects attached to a user when said user is deleted?

I am implementing a system where when a user deletes his/her account posts they have made will be re-associated to an anonymous account so they can still be displayed for other users of my site.

My site has a one_to_many association between users and posts.

There doesn't seem to be a matching option under dependent: _______ as can be seen here https://api.rubyonrails.org/classes/ActiveRecord/Associations/ClassMethods.html#method-i-has_many-label-Options

What I have done (and it is working) is added the following code to my destroy action inside of my user controller

    user = User.find_by(username: params[:username])
    admin_id = User.find_by(email: 'admin_account@gmail.com').id
    user.posts.each do |post|
      post.user_id = admin_id
      post.save
    end
    user.destroy

I figured that this is likely a common enough desire to have a more standard, "best practice" or "Railsy" way of accomplishing it, if there is what is it?

The dependent attribute doesn't have an option for what you are looking for. You can, however, use the before_destroy callback to modify the associated model.

before_destroy :modify_association

def modify_association
  associated_model.update(...)
end

You can read more about it here