add basic storage class and interface

src/main/java/Storage.java

@@ -0,0 +1,11 @@
+public class Storage implements StorageInterface{
+    @Override
+    public void export() {
+
+    }
+
+    @Override
+    public void load() {
+
+    }
+}

src/main/java/StorageInterface.java

@@ -0,0 +1,4 @@
+public interface StorageInterface {
+    public void export();
+    public void load();
+}

src/test/java/StorageTest.java

@@ -0,0 +1,19 @@
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class StorageTest {
+
+    @Test
+    void constructor() {
+        assertInstanceOf(Storage.class, new Storage());
+    }
+
+    @Test
+    void export() {
+    }
+
+    @Test
+    void load() {
+    }
+}