Authentication Stuff

[WZYCX]

Input Sanitisation + Sign up new users.

https://medium.com/firebase-developers/ios-firebase-authentication-sdk-email-and-password-login-6a3bb27e0536

[WZYCX]

Added regex check email function for input sanitisation

func emailCheck(email:String) -> Bool{ return NSPredicate(format: "SELF MATCHES %@", "[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}").evaluate(with: email) }