NotBlank annotation is added.

Author: oguzhan-bolukbas

src/main/java/com/trendyol/recomengine/webservice/resource/Review.java

@@ -7,6 +7,7 @@
  */
 public class Review extends ReviewWithoutUserId {
 
+    @NotBlank
     private final String userId;
 
     /**
@@ -36,4 +37,4 @@ public String getUserId() {
         return userId;
     }
 
-}
+}