func connection(connection:NSURLConnection!, willSendRequestForAuthenticationChallenge challenge:NSURLAuthenticationChallenge!) {

    if challenge.previousFailureCount > 1 {

    } else {
        let creds = NSURLCredential(user: usernameTextField.text, password: passwordTextField.text, persistence: NSURLCredentialPersistence.None)
        challenge.sender.useCredential(creds, forAuthenticationChallenge: challenge)

    }

}