How do I refresh thymeleaf variables in a html page?

Question

I have a sidebar fragment with a list of Projects that the logged in user has access to. When the user creates a new project, he is automatically added into the project and should appear in the list in the sidebar. However, I am unable to refresh that fragment.

Here is the HTML with the list rendering

<ul class="sub-menu">
    <th:block th:each="project : ${#authentication.getPrincipal().getProjects()}">
    <li><a th:text="${project.getProjectName()}" th:href="${'/admin/projects/id/' + project.id}"}></a></li>
    </th:block>
</ul>

Is there a way to refresh this list after the User has created a new Project or when the User has been added into a new Project. Without having to log out and in again to refresh the fragment.