How do you get in casino in sonic adventure?

There's a button on the ground you have to press. With Sonic, pressing it will make a trail of rings appear. Ring dash on them, and you'll hit a button above the casino sign, which will open the casino. Keep in mind the casino is only open at night. With Tails it's the same thing, press the button, and fly up and hit the button above the casino sign. With Knuckles, climb the adjacent building and glide over to hit it.