Add missing ItemStack serializer

src/me/libraryaddict/disguise/utilities/DisguiseUtilities.java

@@ -834,6 +834,7 @@ public class DisguiseUtilities {
         gsonBuilder.registerTypeAdapter(Disguise.class, new SerializerDisguise());
         gsonBuilder.registerTypeAdapter(FlagWatcher.class, new SerializerFlagWatcher());
         gsonBuilder.registerTypeAdapter(PropertyMap.class, new PropertyMap.Serializer());
+        gsonBuilder.registerTypeAdapter(ItemStack.class, new SerializerItemStack());
 
         gson = gsonBuilder.create();
 

src/me/libraryaddict/disguise/utilities/json/SerializerItemStack.java

@@ -0,0 +1,28 @@
+package me.libraryaddict.disguise.utilities.json;
+
+import com.comphenix.protocol.wrappers.WrappedGameProfile;
+import com.google.gson.*;
+import com.mojang.authlib.GameProfile;
+import org.bukkit.inventory.ItemStack;
+
+import java.lang.reflect.Type;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.regex.Pattern;
+
+/**
+ * Created by libraryaddict on 1/06/2017.
+ */
+public class SerializerItemStack implements JsonSerializer<ItemStack>, JsonDeserializer<ItemStack> {
+
+    @Override
+    public JsonElement serialize(ItemStack src, Type typeOfSrc, JsonSerializationContext context) {
+        return context.serialize(src.serialize());
+    }
+
+    @Override
+    public ItemStack deserialize(JsonElement json, Type typeOfT,
+            JsonDeserializationContext context) throws JsonParseException {
+        return ItemStack.deserialize((Map<String, Object>) context.deserialize(json, HashMap.class));
+    }
+}