Why this doesn't count?

Read the hint: “This page is coded to only let in one user (Ronald). But there is no Ronald?! You will need to find a way to add him to the list.”

This means you have to find a way to add the name Ronald to the list… how would you do this? Think hard and have fun ;)

[quote=KanErNogNiksVan]Does this belong to hacking?[/quote]

Strictly speaking, hacking is the art to exploit an object, a system or really anything, to make it work in a way which was not intended by its creator. You are trying to exploit the system so it makes you login as Ronald, when you are not supposed to be able to. So yes, it is hacking.

Congratulations for solving the level by the way!