public static void RemoveIslandDefence(this Entity e, IslandDefence defence)
    {
        List<IslandDefence> defencesCopy = e.islandDefence.defences.Copy();

        defencesCopy.Remove(defence);

        e.ReplaceIslandDefence(defencesCopy);
    }
    public static void AddIslandDefence(this Entity e, string type, int level, int hp)
    {
        IslandDefence defence = new IslandDefence(type, level, hp);

        List<IslandDefence> defencesCopy = e.islandDefence.defences.Copy();

        defencesCopy.Add(defence);

        e.ReplaceIslandDefence(defencesCopy);
    }