Improve initialization in test_user

src/main.rs

@@ -255,10 +255,11 @@ mod tests {
     use crate::User;
 
     fn test_user(name: &str, discriminator: u16) -> User {
-        let mut user = User::default();
-        user.name = name.to_owned();
-        user.discriminator = discriminator;
-        user
+        User {
+            name: name.to_owned(),
+            discriminator,
+            ..Default::default()
+        }
     }
 
     #[test]