Honestly, my current solution to that is to get my current directory correct when I start (:cd ~/Programming/project) and then just :e app/controllers/users_con

Honestly, my current solution to that is to get my current directory correct when I start (:cd ~/Programming/project) and then just :e app/controllers/users_controller.rb when I need a file. Tab completion makes it fast enough that it's not worth optimizing faster.