public function delete($id)
 {
     try {
         VelocityUnitModel::find($id)->delete();
         $alert['msg'] = 'This velocity unit has been deleted successfully';
         $alert['type'] = 'success';
     } catch (\Exception $ex) {
         $alert['msg'] = 'This velocity unit  focus has been already used';
         $alert['type'] = 'danger';
     }
     return Redirect::route('admin.velocity')->with('alert', $alert);
 }