chore: #be drop prototype tables

backend/migrations/20220404140016_drop_prototype.ts

+import { Knex } from "knex";
+
+export async function up(knex: Knex): Promise<void> {
+  return knex.schema.dropTable("game_results").dropTable("images");
+}
+
+export async function down(knex: Knex): Promise<void> {
+  // NOTE: we're not interested in reversing this.
+}