diff --git a/ass1-jpa/src/main/java/dst/ass1/jpa/model/impl/PlatformUser.java b/ass1-jpa/src/main/java/dst/ass1/jpa/model/impl/PlatformUser.java
index d8bc61a..9302853 100644
--- a/ass1-jpa/src/main/java/dst/ass1/jpa/model/impl/PlatformUser.java
+++ b/ass1-jpa/src/main/java/dst/ass1/jpa/model/impl/PlatformUser.java
@@ -9,7 +9,7 @@ import javax.persistence.MappedSuperclass;
 import java.io.Serializable;
 
 @MappedSuperclass
-public class PlatformUser implements IPlatformUser, Serializable {
+public abstract class PlatformUser implements IPlatformUser, Serializable {
     @Id @GeneratedValue
     protected Long id;