feature: Add optimistic offline lock (#1306) (#2551)

optimistic-offline-lock/src/main/java/com/iluwatar/model/Card.java

@@ -0,0 +1,37 @@
+package com.iluwatar.model;
+
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+/**
+ * Bank card entity.
+ */
+@Data
+@Builder
+@NoArgsConstructor
+@AllArgsConstructor
+public class Card {
+
+  /**
+   * Primary key.
+   */
+  private long id;
+
+  /**
+   * Foreign key points to card's owner.
+   */
+  private long personId;
+
+  /**
+   * Sum of money.
+   */
+  private float sum;
+
+  /**
+   * Current version of object.
+   */
+  private int version;
+}