If you have a Facebook account, you can connect it to SuperCity to be able to add your Facebook Friends and restore your account on other devices.
Tap the settings button on the left side of your screen.
Tap "Log in" in the settings window.
You will be redirected to Facebook. If you aren't authorized on the site, you will be prompted to enter your account data in order to log in. Enter your email/phone number and your password and tap "Log in".
Once you're authorized, you will be asked to confirm your decision. Tap "Continue" and you will be taken back to the game.