Fix the undefined stars in linker

strategies/linker.go

@@ -48,7 +48,7 @@ func (ls *LinkerStrategy) attack(stars []*models.Star, flights []models.Flight,
 		// Determine target for this source
 		for j, t := range stars {
 			// Only target non-owned or enemy stars
-			if t.Friendly() || t.OwnedByMe() {
+			if !t.Unowned() || !t.Enemy() {
 				continue
 			}