Resolve roles.yml file from Rails.root

[gazayas]

Closes #688.

As a side note, I didn't add #{Rails.root} the following lines because it was throwing an error when trying to run migrations in the starter repository:

bullet_train-core/bullet_train-roles/lib/models/role.rb

Lines 7 to 8 in 445b8e6

	set_root_path "config/models"
	set_filename "roles"

bullet_train-core/bullet_train-roles/test/dummy/config/application.rb

Lines 34 to 35 in 445b8e6

	Role.set_root_path("config/models")
	Role.set_filename("roles")

set_root_path is an ActiveHash method, and it looks like it already looks for a yml file based off of the root path. This can be inferred from the following in the documentation:

By default, this class will look for a yml file named "countries.yml" in the same directory as the file. You can either change the directory it looks in, the filename it looks for, or both:

class Country < ActiveYaml::Base
  set_root_path "/u/data"
  set_filename "sample"
end

The above example will look for the file "/u/data/sample.yml".

[gazayas]

Since we're currently out of CI credits I ran the super scaffolding tests locally and everything's working fine.

[jagthedrummer]

Hmmm... this looks like it should work, but it doesn't seem to change anything. The tests are still passing with this change, but I'd expect them to fail since the fixture file would be in the wrong place. Just to confirm I pulled down this branch and tried moving the fixture file into the dummy app where it should go, and then the tests fail due to not being able to find the file.

Webhooks::Incoming::BulletTrainWebhooksControllerTest
  test_should_get_incoming_webhook                               ERROR (0.46s)
Minitest::UnexpectedError:         Errno::ENOENT: No such file or directory @ rb_sysopen - config/models/roles.yml