Mod bugfixes

core/src/mindustry/io/JsonIO.java

@@ -8,6 +8,7 @@ import mindustry.ctype.*;
 import mindustry.game.*;
 import mindustry.type.*;
 import mindustry.world.*;
+import mindustry.world.meta.*;
 
 import java.io.*;
 
@@ -111,6 +112,18 @@ public class JsonIO{
             }
         });
 
+        json.setSerializer(Attribute.class, new Serializer<>(){
+            @Override
+            public void write(Json json, Attribute object, Class knownType){
+                json.writeValue(object.name);
+            }
+
+            @Override
+            public Attribute read(Json json, JsonValue jsonData, Class type){
+                return Attribute.get(jsonData.asString());
+            }
+        });
+
         json.setSerializer(Item.class, new Serializer<>(){
             @Override
             public void write(Json json, Item object, Class knownType){