useful.sql: add maintainers to SQL output

scripts/useful.sql

@@ -1,7 +1,7 @@
 -- some useful SQL commands (for PostgreSQL)
 
 -- show build log
-select id, ts, pkgbase, nv_version, pkg_version, elapsed, result, cputime, case when elapsed = 0 then 0 else cputime * 100 / elapsed end as "cpu%", round(memory / 1073741824.0, 3) as "memory (GiB)", substring(msg for 20) as msg, build_reasons from pkglog order by id desc limit 10;
+select id, ts, pkgbase, nv_version, pkg_version, elapsed, result, cputime, case when elapsed = 0 then 0 else cputime * 100 / elapsed end as "cpu%", round(memory / 1073741824.0, 3) as "memory (GiB)", substring(msg for 20) as msg, build_reasons, (select array_agg(github) from  jsonb_to_recordset(maintainers) as m(github text)) as maintainers from pkglog order by id desc limit 10;
 
 -- show current build status and expected time
 select index, c.pkgbase, updated_at, status, elapsed as last_time, c.build_reasons from pkgcurrent as c left join lateral (