Use RoR4.2 style Selector matchers
Use RoR4.2 style Selector matchers

- should Finish [Pivotal #108925894](https://www.pivotaltracker.com/story/show/108925894), but I cannot test immediately:
- fix exposes later Error in the LurkerTest

raysuelzer/mushroom-observer,JoeCohen/mushroom-observer,raysuelzer/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,JoeCohen/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,raysuelzer/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,raysuelzer/mushroom-observer