Rails 5 w/ Postgres: Use UUID instead of a numeric ID as primary keys

00000000000000_enable_uuid.rb

# db/migrate/00000000000000_enable_uuid.rb

class EnableUuid < ActiveRecord::Migration[5.0]
  def change
    execute 'create extension "uuid-ossp"'
    enable_extension 'uuid-ossp'
  end
end

README.md

• No need to change migrations
• Problems with first and last, see: https://github.com/fnando/ar-uuid#disadvantages

Gemfile

gem 'ar-uuid'