public function getAuthenticationUrl()
    {
        $params = [
            'client_id' => $this->clientId,
            'scope' => $this->scopes,
            'state' => $this->state,
            'response_type' => 'code',
            'redirect_uri' => $this->redirectUrl,
        ];

        return 'https://medium.com/m/oauth/authorize?' . http_build_query($params);
    }