Bump opium, add dbmate

db/migrations/20250728060412_create_index.sql

@@ -0,0 +1,15 @@
+-- migrate:up
+CREATE TABLE yore.day_index (
+  id  bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+  day date NOT NULL UNIQUE
+);
+
+CREATE TABLE yore.day_file (
+  id            bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+  day_id        bigint REFERENCES yore.day_index(id),
+  relative_path text NOT NULL
+);
+
+-- migrate:down
+DROP TABLE yore.day_file;
+DROP TABLE yore.day_index;