Adds an AdminPanel with currently active registration tokens.

backend/migrations/2022-06-04-141858_registration_tokens/up.sql

@@ -0,0 +1,11 @@
+-- Your SQL goes here
+
+create table registration_tokens (
+    id UUID PRIMARY KEY,
+    token CHARACTER(32) NOT NULL,
+    single_use BOOLEAN NOT NULL,
+    expires TIMESTAMPTZ
+);
+
+ALTER TABLE gamenight
+ALTER datetime TYPE TIMESTAMPTZ using datetime::timestamp;