private function registrationChecks(UserDAO $userDAO, RegisterData $userRegData)
 {
     $password = password_hash($userRegData->getPassword(), PASSWORD_BCRYPT);
     if (password_verify($userRegData->getPasswordAgain(), $password)) {
         if (!$userDAO->doNicknameExistInDB($userRegData->getNickname())) {
             return true;
         } else {
             throw new CustomException("Unfortunately username you entered is already taken. :( Try another one!");
         }
     } else {
         throw new CustomException("Passwords you entered do not match. :( Try again!");
     }
 }
 /**
  * This method gets users nickname
  * @param $userID
  * @return mixed
  */
 public function getNicknameByID($userID)
 {
     $userDAO = new UserDAO();
     return $userDAO->getNicknameByIDFromDB($userID);
 }