carry the code from core-java to data-structures module

data-structures/src/main/java/com/baeldung/printbinarytree/BinaryTreeModel.java

@@ -0,0 +1,37 @@
+package com.baeldung.printbinarytree;
+
+public class BinaryTreeModel {
+
+    private Object value;
+    private BinaryTreeModel left;
+    private BinaryTreeModel right;
+
+    public BinaryTreeModel(Object value) {
+        this.value = value;
+    }
+
+    public Object getValue() {
+        return value;
+    }
+
+    public void setValue(Object value) {
+        this.value = value;
+    }
+
+    public BinaryTreeModel getLeft() {
+        return left;
+    }
+
+    public void setLeft(BinaryTreeModel left) {
+        this.left = left;
+    }
+
+    public BinaryTreeModel getRight() {
+        return right;
+    }
+
+    public void setRight(BinaryTreeModel right) {
+        this.right = right;
+    }
+
+}