added next method for Color

Projekte/mdga/model/src/main/java/pp/mdga/game/Color.java

@@ -1,9 +1,12 @@
 package pp.mdga.game;
 
 public enum Color {
-    ARMY,
+    AIRFORCE,
-    NAVY,
     CYBER,
-    AIRFORCE
+    NAVY,
+    ARMY;
 
+    public Color next() {
+        return values()[(ordinal() + 1) % values().length];
+    }
 }