timestamp accounts

ops/migrations/20180913000513_create_accounts.js

@@ -1,6 +1,7 @@
 exports.up = async knex => {
     return knex.schema.createTable('accounts', table => {
         table.uuid('id').primary();
+        table.timestamps();
         table.string('name', 42).notNullable().unique();
         table.string('password').notNullable();
         table.string('token', 64).notNullable();