hardcoded return_url

[evgeny-s]

Hello, John.
We using your Lti2 gem for TC and TP implementation.
Could you please fix hardcoded return_url to request.original_url:
lti2_tp/app/controllers/lti2_tp/registration_controller.rb:

50| redirect_to "/lti_registration_wips?registration_id=#{@registration.id}&return_url=/lti2_tp/registrations"

and

136| redirect_to "/lti_registration_wips?registration_id=#{@registration.id}&return_url=/lti2_tp/registrations"

Thank you!