add files meta data

backend/internal/db/queries/files.sql

@@ -0,0 +1,15 @@
+-- name: GetFile :one
+SELECT * FROM files
+WHERE id = ? LIMIT 1;
+
+-- name: ListFiles :many
+SELECT * FROM files
+ORDER BY name;
+
+-- name: CreateFile :one
+INSERT INTO files (
+  name,storage_key,checksum,created_at,updated_at,deleted_at
+) VALUES (
+  ?, ?, ?,date(),date(),date()
+)
+RETURNING *;