change to 'apply to staff' instead of 'sign up to staff'

this will need to be integrated later with Vicki's 8.5 changes that do the same thing

saying that this fixes #251 for the sake of getting this thing on the road
Merge pull request #256 from EliAndrewC/ftr_staffing_changes

change to 'apply to staff' instead of 'sign up to staff'