I know some people don’t like using them, but it’s way better in my opinion to use an ENUM if you’re using PostgreSQL. It uses the same space as an int, but it will be readable and better in terms of data integrity (you can’t have a value that doesn’t exist).
There are some caveats, but I never had any problems with them.
CREATE TYPE gender AS ENUM ('male', 'female', 'other');
