public function positionsJson(Request $request)
 {
     $by = $request->input('by', 'ministry');
     if ($by === 'ministry') {
         return Ministry::has('volunteer_positions')->with('volunteer_positions.skills')->orderBy('title')->get();
     } else {
         return VolunteerSkill::has('volunteer_positions')->with('volunteer_positions')->get();
     }
 }