Nicer error when app with desired Rails version doesn't exist
Nicer error when app with desired Rails version doesn't exist

arkency/rails_event_store,mpraglowski/rails_event_store,RailsEventStore/rails_event_store,arkency/rails_event_store,mpraglowski/rails_event_store,mpraglowski/rails_event_store,arkency/rails_event_store,RailsEventStore/rails_event_store,RailsEventStore/rails_event_store,mpraglowski/rails_event_store,arkency/rails_event_store,RailsEventStore/rails_event_store