...
{% include 'message.html' %}
...
<!-- and at the end:-->
<script src="{% static 'js/jquery-3.4.1.min.js' %}"></script>
<script src="{% static 'js/bootstrap.min.js' %}"></script>
{% if messages %}
<script>
{% for message in messages %}
$(document).ready(function () {
$('.toast').toast('show');
});
{% endfor %}
</script>
{% endif %}