public function showCustomersOf($groupId)
 {
     $group = CustomerGroup::findOrFail($groupId);
     return view('customer.show-customers-of')->with('group', $group)->with('body', 'customers-of-' . $groupId);
 }
 public function showMembers($groupId)
 {
     $group = CustomerGroup::findOrFail($groupId);
     return view('customer-group.members')->with('group', $group);
 }