fix Django debug toolbar after its upgrade

awx/urls.py

@@ -2,6 +2,7 @@
 # All Rights Reserved.
 
 from django.conf.urls import url, include
+from django.conf import settings
 from awx.main.views import (
     handle_400,
     handle_403,
@@ -21,6 +22,19 @@ urlpatterns = [
     url(r'^(?:api/)?500.html$', handle_500),
 ]
 
+if settings.SETTINGS_MODULE == 'awx.settings.development':
+    try:
+        import debug_toolbar
+        urlpatterns += [
+            # for Django version 2.0
+            # path('__debug__/', include(debug_toolbar.urls)),
+
+            # TODO: this is the Django < 2.0 version, REMOVEME
+            url(r'^__debug__/', include(debug_toolbar.urls))
+        ]
+    except ImportError:
+        pass
+
 handler400 = 'awx.main.views.handle_400'
 handler403 = 'awx.main.views.handle_403'
 handler404 = 'awx.main.views.handle_404'