add Stock Entity, Repositoy and Service

src/main/java/fr/eni/demo/bll/StockService.java

@@ -0,0 +1,17 @@
+package fr.eni.demo.bll;
+
+import fr.eni.demo.bo.Stock;
+import fr.eni.demo.dal.StockRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class StockService {
+
+  @Autowired
+  private StockRepository stockRepository;
+
+  public void add(Stock stock) {
+    stockRepository.save(stock);
+  }
+}