I recently needed to set it up for an older Rails app, still running Rails 2. Here’s how I did it.
Add the gem to your gemfile. This version of bullet works with Rails 2.
gem 'bullet', '1.7.6'
Next, you need to add the bullet initializer to your development.rb.
config.after_initialize do Bullet.enable = true Bullet.alert = true Bullet.bullet_logger = true Bullet.console = true end
And that’s it! You’ll now get alerts whenever N+1 queries are encountered.