@Override
    public int hashCode() {
        return Objects.hash(subject, html, plain, category);
    }
Email template entry in the format stored in the template file index (notification-template-index).

@author Marc Savy {@literal <marc@blackparrotlabs.io>}
manager/api/rest-impl/src/main/java/io/apiman/manager/api/notifications/email/EmailTemplateFileEntry.java