Fix the failing building
Fix the failing building

The misuse of a class variable instead of a method will lead to a nil,
making the tests to fail.

fidalgo/rails_api_auth,simplabs/rails_api_auth,fidalgo/rails_api_auth,simplabs/rails_api_auth,simplabs/rails_api_auth,ibroadfo/rails_api_auth,fidalgo/rails_api_auth,ibroadfo/rails_api_auth,ibroadfo/rails_api_auth