Fix Serializable implementation

build.gradle

@@ -10,7 +10,7 @@ plugins {
 }
 
 group 'com.github.ayltai'
-version '0.2.6'
+version '0.2.7'
 
 sourceCompatibility = 8
 targetCompatibility = 8

src/main/java/com/github/ayltai/gradle/plugin/Variables.java

@@ -1,6 +1,9 @@
 package com.github.ayltai.gradle.plugin;
 
 import java.io.File;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
 import java.util.ArrayList;
 import java.util.List;
 import javax.annotation.Nonnull;
@@ -23,4 +26,12 @@ public <T> void var(@Nonnull final String name, @Nullable final T value) {
     public void file(@Nonnull final File file) {
         this.files.add(file);
     }
+
+    private static void writeObject(@Nonnull final ObjectOutputStream outputStream) throws IOException {
+        outputStream.defaultWriteObject();
+    }
+
+    private static void readObject(@Nonnull final ObjectInputStream inputStream) throws IOException, ClassNotFoundException {
+        inputStream.defaultReadObject();
+    }
 }