Fix migration package name mismatch

db/migrations/20201010162350_add_album_size.go

@@ -0,0 +1,34 @@
+package migrations
+
+import (
+	"context"
+	"database/sql"
+
+	"github.com/pressly/goose/v3"
+)
+
+func init() {
+	goose.AddMigrationContext(Up20201010162350, Down20201010162350)
+}
+
+func Up20201010162350(_ context.Context, tx *sql.Tx) error {
+	_, err := tx.Exec(`
+alter table album
+	add size integer default 0 not null;
+create index if not exists album_size
+	on album(size);
+
+update album set size = ifnull((
+select sum(f.size)
+from media_file f
+where f.album_id = album.id
+), 0)
+where id not null;`)
+
+	return err
+}
+
+func Down20201010162350(_ context.Context, tx *sql.Tx) error {
+	// This code is executed when the migration is rolled back.
+	return nil
+}