So, I was just thinking about this a little more and I just remembered that there is a SQL
COMMENT command in PostgreSQL.
This way, documentation of columns can be done in migrations and then generated from a SQL query I found here:
FROM pg_catalog.pg_class c, information_schema.columns cols
WHERE cols.table_catalog = 'db_name' AND
cols.table_schema = 'schema_name' AND
cols.table_name = 'table_name' AND
cols.table_name = c.relname;