set templates collection mutable

Author: Dytanic

cloudnet-lib/src/main/java/de/dytanic/cloudnet/lib/server/ServerGroup.java

@@ -15,6 +15,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 
 /**
  * Created by Tareko on 21.05.2017.
@@ -78,7 +79,7 @@ public ServerGroup(String name, Collection<String> wrapper, boolean kickedForceF
                 new PriorityConfig(groupPriority, priorityForGroupOnlineCount)
         );
 
-        this.templates = Arrays.asList(new Template("default", TemplateResource.LOCAL, null, new String[]{}, new ArrayList<>()));
+        this.templates = new ArrayList<>(Collections.singletonList(new Template("default", TemplateResource.LOCAL, null, new String[]{}, new ArrayList<>())));
     }
 
     public SimpleServerGroup toSimple()