public function verify_email()
 {
     require_once WPPR_PLUGIN_DIR . '/models/signup-model.php';
     $model = new Signup_Model();
     $redirect_url = home_url();
     if (isset($_GET['key']) && !empty($_GET['key']) && isset($_GET['email']) && !empty($_GET['email'])) {
         //Sanitize query
         $model->key = sanitize_key($_GET['key']);
         $model->email = sanitize_email($_GET['email']);
         $valid = $model->confirm_verification_key();
         if ($valid) {
             // reset verification key
             update_user_meta($model->user_id, 'is_email_verified', 1, 0);
             update_user_meta($model->user_id, 'email_verification_key', null, $this->key);
             $redirect_msg = 'Way to go runner, your email was successfully verified!';
         } else {
             $redirect_msg = 'Oops! the keys or email is either invalid or expired!';
         }
     } else {
         $redirect_msg = 'Oops! the parameters is invalid!';
     }
     $this->redirect_to($redirect_msg, $redirect_url);
 }