make it possible to have username

src/PersistentData/Model/User.php

@@ -8,12 +8,14 @@ class User extends Model implements IUser
 {
     protected static string $table = 'users';
 
-    protected static array $fields = ['email', 'password', 'type', 'google_sub', 'created'];
+    protected static array $fields = ['email', 'username', 'password', 'type', 'google_sub', 'created'];
 
     private static array $types = ['user', 'admin'];
 
     private string $email = '';
 
+    private ?string $username = null;
+
     private ?string $password = null;
 
     private string $type = 'user';
@@ -27,6 +29,11 @@ class User extends Model implements IUser
         $this->email = $email;
     }
 
+    public function setUsername(?string $username): void
+    {
+        $this->username = $username;
+    }
+
     public function setPassword(?string $hashedPassword): void
     {
         $this->password = $hashedPassword;
@@ -64,6 +71,11 @@ class User extends Model implements IUser
         return $this->email;
     }
 
+    public function getUsername(): ?string
+    {
+        return $this->username;
+    }
+
     public function getPassword(): ?string
     {
         return $this->password;