added Tests and fix addUserEvent

src/main/java/mops/gruppen2/domain/User.java

@@ -2,12 +2,16 @@ package mops.gruppen2.domain;
 
 import lombok.AllArgsConstructor;
 import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.Value;
 
-@Data
+@Value
 @AllArgsConstructor
+@EqualsAndHashCode(exclude = {"givenname", "familyname", "email"})
 public class User {
 
     String user_id;
+
     String givenname;
     String familyname;
     String email;