Room per User and KalenderTag

src/main/resources/db/migration/V0003__room.sql

@@ -0,0 +1,10 @@
+create table room (
+    id bigint not null primary key,
+    name varchar not null unique
+);
+
+alter table users add column room_id bigint references room;
+alter table kalendertag add column room_id bigint references room;
+
+alter table kalendertag drop constraint kalendertag_day_key;
+