Enforce CSRF check for acknowledging toasts

bookmarks/templates/bookmarks/layout.html

@@ -30,12 +30,15 @@
 <header>
     {% if has_toasts %}
     <div class="toasts container grid-lg">
+      <form action="{% url 'bookmarks:toasts.acknowledge' %}?return_url={{ request.path | urlencode }}" method="post">
+        {% csrf_token %}
         {% for toast in toast_messages %}
             <div class="toast">
                 {{ toast.message }}
-                <a href="{% url 'bookmarks:toasts.acknowledge' toast.id %}?return_url={{ request.path | urlencode }}" class="btn btn-clear float-right"></a>
+                <button type="submit" name="toast" value="{{ toast.id }}" class="btn btn-clear float-right"></button>
             </div>
         {% endfor %}
+      </form>
     </div>
     {% endif %}
     <div class="navbar container grid-lg">