chore: cleanup DB migration script (denoland#612)

This code is no longer needed.

tasks/db_migrate.ts

@@ -12,57 +12,3 @@
  * deno task db:migrate
  * ```
  */
-import {
-  createItem,
-  createVote,
-  deleteVote,
-  type Item,
-  kv,
-  User,
-} from "@/utils/db.ts";
-import { ulid } from "std/ulid/mod.ts";
-
-interface OldItem extends Item {
-  createdAt: Date;
-}
-
-if (!confirm("WARNING: The database will be migrated. Continue?")) Deno.exit();
-
-const iter1 = kv.list<OldItem>({ prefix: ["items"] });
-for await (const oldItemEntry of iter1) {
-  if (oldItemEntry.value.createdAt) {
-    const newItem = {
-      id: ulid(new Date(oldItemEntry.value.createdAt).getTime()),
-      userLogin: oldItemEntry.value.userLogin,
-      url: oldItemEntry.value.url,
-      title: oldItemEntry.value.title,
-      score: oldItemEntry.value.score,
-    };
-    await createItem(newItem);
-    const iter2 = kv.list<User>({
-      prefix: ["users_voted_for_item", oldItemEntry.value.id],
-    });
-    for await (const userEntry of iter2) {
-      await deleteVote({
-        itemId: oldItemEntry.value.id,
-        userLogin: userEntry.value.login,
-      });
-      await deleteVote({
-        itemId: newItem.id,
-        userLogin: userEntry.value.login,
-      });
-      await createVote({
-        itemId: newItem.id,
-        userLogin: userEntry.value.login,
-      });
-    }
-    await kv.delete(oldItemEntry.key);
-  }
-}
-
-const iter3 = kv.list<OldItem>({ prefix: ["items_by_user"] });
-for await (const { key, value } of iter3) {
-  if (value.createdAt) await kv.delete(key);
-}
-
-kv.close();