added general logic for easydrop core

src/main/java/de/rwu/easydrop/model/Offer.java

@@ -0,0 +1,52 @@
+package de.rwu.easydrop.model;
+
+import java.util.Date;
+
+
+import lombok.Data;
+
+/**
+ * An Offer.
+ *
+ * @since 0.3.0
+ */
+
+@Data
+public class Offer {
+    /*
+     * The product that our software buys
+     */
+    Product sourceProduct;
+
+    /*
+     * The product that our software sells
+     */
+    Product saleProduct;
+
+    /*
+     * Boolean to check if sourceProduct is still available on source website
+     */
+    boolean availability;
+
+    /*
+     * Date of the creation of the offer
+     * NOTE: Use Timestamp? https://docs.oracle.com/javase/8/docs/api/java/sql/Timestamp.html
+     */
+    Date creationDate;
+
+    /*
+     * Date of last update of the offer on the destination website (API)
+     */
+    Date upDate;
+
+    /*
+     * Date of last check if offer is still valid
+     */
+    Date checkDate;
+
+
+
+
+
+    
+}