add app name to follow good practice

coinmanager/coinc/templates/coinc/country.html

@@ -1,7 +1,7 @@
     <table>
       <thead>
         <tr>
-          <td colspan="4"><a href="{% url 'country' country.name_iso %}">{{ country.name }}</a><td>
+          <td colspan="4"><a href="{% url 'coinc:country' country.name_iso %}">{{ country.name }}</a><td>
           <td colspan="2">x €</td>
           <td colspan="9"></td>
         </tr>

coinmanager/coinc/urls.py

@@ -23,6 +23,7 @@ from django.urls import path
 from . import views
 
 
+app_name = 'coinc'
 urlpatterns = [
     path('', views.index, name='index'),
     path('statistik', views.statistic, name='statistic'),