Rails Engine + Mongoid: No configuration could be found for a session named 'default'

I've created a Rails Mountable App and added 'mongoid' and 'rspec' gem's. If I try to run my specs now I get the following error: ``` Mongoid::Errors::NoSessionConfig: Problem: No configuration could be found for a session named 'default'. Summary: When attempting to create the new session, Mongoid could not find a session configuration for the name: 'default'. This is necessary in order to know the host, port, and options needed to connect. Resolution: Double check your mongoid.yml to make sure under the sessions key that a configuration exists for 'default'. If you have set the configuration programatically, ensure that 'default' exists in the configuration hash. ``` When I add the `Mongoid.load!(Rails.root.join("config", "mongoid.yml"))` line to `spec_helper.rb` everything works normal. Why is that and how can I get the functionality like in a normal Rails app where I don't need to call the load function? mongoid.yml ``` development: sessions: default: database: dummy_development hosts: - localhost:27017 options: options: test: sessions: default: database: dummy_test hosts: - localhost:27017 options: consistency: :strong max_retries: 1 retry_interval: 0 ``` Versions: ``` gem 'rails', '~> 3.2.12' gem 'mongoid', '~> 3.1' gem 'rspec-rails', '~> 2.13' ```