add a stub for Caddyfile controller

internal/machine/store/store.go

@@ -88,7 +88,7 @@ func (s *Store) ListMachines(ctx context.Context) ([]*pb.MachineInfo, error) {
 }
 
 // SubscribeMachines returns a list of machines and a channel that signals changes to the list. The channel doesn't
-// receive any values, it's just signals when a machine has been added, updated, or deleted in the database.
+// receive any values, it just signals when a machine has been added, updated, or deleted in the database.
 func (s *Store) SubscribeMachines(ctx context.Context) ([]*pb.MachineInfo, <-chan struct{}, error) {
 	sub, err := s.corro.SubscribeContext(ctx, "SELECT info FROM machines ORDER BY name", nil, false)
 	if err != nil {