group check template tag

app/export/templatetags/group_check.py

@@ -0,0 +1,9 @@
+from django import template
+from django.contrib.auth.models import Group 
+
+register = template.Library()
+
+@register.filter(name='group_check')
+def has_group(user, group_name): 
+    group = Group.objects.get(name=group_name) 
+    return True if group in user.groups.all() else False

app/templates/partials/_navbar.html

@@ -1,4 +1,6 @@
 {% load static %}
+{% load group_check %}
+
 {% if user.is_authenticated %}
 
 <nav class="navbar navbar-expand-lg navbar-dark bg-primary sticky-top">
@@ -30,11 +32,14 @@
                         <a class="nav-link {% if '/costs/all' in request.path %} active {% endif %}"
                             href="{% url 'costs_all' %}">alle Kosten</a>
                     </li>
+
+                    {% if request.user|group_check:"data-export" %} 
                         <li class="nav-item">
                             <a class="nav-link {% if '/export' in request.path %} active {% endif %}"
                             href="{% url 'site_exports' %}">Daten-Export</a>
                         </li>
                     {% endif %}
+                {% endif %}
             </ul>
 
             <ul class="navbar-nav pull-right">