How do I remove ActiveRecord from an existing Rails 4 Application?

I started off a Ruby on Rails Project which includes a simple recommender system with ActiveRecord and Neography. Now I found out about neo4j.rb, which is going to simplify my life by a lot. :-)

I learned by now, that I could create a new Application without ActiveRecord as follows:

rails new xyz -O

I could do that and copy paste most of my files / code into that new project. Or is there an easier way?

I am still thinking about if that step is even necessary. Is it possible to use both neo4j.rb and ActiveRecord in parallel? I am thinking of running the authentication system (e.g. Devise) with ActiveRecord and my recommender system in neo4j. Does anyone have experiences with such an approach?

Follow these steps

1. Remove database adapter gems from your Gemfile, e.g., mysql2, sqlite3, etc

2. From application.rb, remove require 'rails/all' and require frameworks (among those available in your rails version, the list varies, do not just copy) you want to use, for example:

   require "action_controller/railtie"
   require "action_mailer/railtie"
   require "sprockets/railtie"
   require "rails/test_unit/railtie"
   

3. Delete database.yml, schema.rb and all the migrations

4. Delete migration checks from test/test_helper.rb
5. Delete all activerecord related configuration from config/environments

Hope this helps!

Source - Disable ActiveRecord for Rails 4