function add_user($nom,$prenom,$email){

    $stmt = $GLOBALS['bdd']->prepare("SELECT email FROM users WHERE email=:email");
    $stmt->execute(array(':email'=>$email));

    if($stmt->rowCount() == 0){
        $rsp = $GLOBALS['bdd']->prepare("INSERT INTO users(nom,prenom,email) VALUES(:nom,:prenom,:email)");
        $rsp->execute(array(
            ':nom' => $nom,
            ':prenom' => $prenom,
            ':email' => $email
            ));

        return true;
    }else{
        return false;
    }


}