trying like that

django_code/django_code/hosts.py

@@ -1,7 +1,8 @@
+from django.conf import settings
 from django_hosts import patterns, host
 
 host_patterns = patterns(
     "path.to",
-    host(r"django-testing", "urls.py", name="django-testing"),
-    host(r"redirect", "redirect_urls.py", name="redirect"),
+    host(r"django-testing", settings.ROOT_URLCONF, name="django-testing"),
+    host(r"redirect", 'website_redirectionapp.urls', name="redirect"),
 )

django_code/django_code/settings.py

@@ -54,6 +54,9 @@ MIDDLEWARE = [
 ]
 
 ROOT_URLCONF = 'django_code.urls'
+ROOT_HOSTCONF = 'django_code.hosts'
+DEFAULT_HOST = 'django-tryton'
+
 
 TEMPLATES = [
     {

django_code/django_code/urls.py

@@ -27,8 +27,6 @@ from stash_management import apps as stashapp
 from stash_management import views as stashview
 from website_redirection import apps as website_redirectionapp
 
-ROOT_HOSTCONF = 'hosts.py'
-DEFAULT_HOST = 'django-testing.tryton.geeraert.eu'
 
 urlpatterns = [
 #    path('admin/', admin.site.urls),