How to: Migration files
Migration files are very simple, and are stored in `./db/migrations` by default. You can create a new migration file named `[date]_create_users.sql` by running `dbmate new create_users`.
Here is an example:

```sql
-- migrate:up
create table users (
  id integer,
  name varchar(255),
);

-- migrate:down
drop table if exists users;
```

Both up and down migrations are stored in the same file, for ease of editing. Both up and down directives are required, even if you choose not to implement the down migration.

When you apply a migration dbmate only stores the version number, not the contents, so you should always rollback a migration before modifying its contents. For this reason, you can safely rename a migration file without affecting its applied status, as long as you keep the version number intact.