Added a .ruby-version file.
Added a .ruby-version file.

YorickPeterse/oga,ttasanen/oga,dfockler/oga,YorickPeterse/oga,ttasanen/oga,altmetric/oga,altmetric/oga,jeffreybaird/oga,altmetric/oga,YorickPeterse/oga,ttasanen/oga,ttasanen/oga,YorickPeterse/oga,dfockler/oga,altmetric/oga,jeffreybaird/oga,dfockler/oga,jeffreybaird/oga,dfockler/oga,jeffreybaird/oga,YorickPeterse/oga,altmetric/oga,dfockler/oga,ttasanen/oga,jeffreybaird/oga