Using Mongoid with Rails 4

Mongoid 3 is only compatible with Rails 3.x. Rails 4 requires Mongoid 4.

However, as of this writing, Mongoid 4 is still in development. I’ve had success using the master branch though.

In your Gemfile:

1gem 'mongoid', github: 'mongoid/mongoid'
3# and if you use Sidekiq + Kiqstand:
4gem 'kiqstand', github: 'mongoid/kiqstand'
tags: rails, rails4, mongoid