Upgrade to Django 2.1 (#710)

* Upgrade to Django 2.0

* more models

* i18n foo

* Update setup.py

* Fix Sentry exception PRETIXEU-JC

* Enforce slug uniqueness

* Import sorting

* Upgrade to Django 2.1

* Travis config

* Try to fix PostgreSQL failure

* Smaller test matrix

* staticfiles→static

* Include request in all authenticate() calls

src/pretix/multidomain/plugin_handler.py

@@ -7,5 +7,5 @@ def plugin_event_urls(urllist, plugin):
             plugin_event_urls(entry.url_patterns, plugin)
         elif hasattr(entry, 'callback'):
             entry.callback = _event_view(entry.callback, require_plugin=plugin,
-                                         require_live=getattr(entry, '_require_live', True))
+                                         require_live=getattr(entry.pattern, '_require_live', True))
     return urllist