Edited user to contain nickname

Closes #6 (closed)

src/main/java/edu/ntnu/idatt2106/backend/model/user/User.java

@@ -17,13 +17,14 @@ public class User {
     @Id
     private String email;
 
+    private String nickname;
     private Long phoneNumber;
     private String address;
     private Role role;
     private byte[] password;
     private byte[] salt;
 
-    public User(String email, Long phoneNumber, String address, Role role) {
+    public User(String email, String nickname, Long phoneNumber, String address, Role role) {
         this.email = email;
         this.address = address;
         this.phoneNumber = phoneNumber;