Roles assigned to each user POSTGRES i'm trying to make a query that shows the users and all the roles that they have, i already know how to ask about the roles of one particular user:

 SELECT oid, rolname FROM pg_roles WHERE
 pg_has_role( 'name_of_user', oid, 'member');


Any idea how to do it?
USERS are themselves ROLES that can login. CREATE USER is actually just an alias. What you probably want is some kind of query that psql issues with \du as a starting point. You can see what psql issues with -E,

********* QUERY **********
SELECT r.rolname, r.rolsuper, r.rolinherit,
  r.rolcreaterole, r.rolcreatedb, r.rolcanlogin,
  r.rolconnlimit, r.rolvaliduntil,
  ARRAY(SELECT b.rolname
        FROM pg_catalog.pg_auth_members m
        JOIN pg_catalog.pg_roles b ON (m.roleid = b.oid)
        WHERE m.member = r.oid) as memberof
, r.rolreplication
, r.rolbypassrls
FROM pg_catalog.pg_roles r
ORDER BY 1;
**************************