Add cronjob to reindex the database every month

[abrahammartin]

jw35 said:

Postgres documentation (https://www.postgresql.org/docs/9.5/routine-reindex.html) says

"B-tree index pages that have become completely empty are reclaimed for re-use. However, there is still a possibility of inefficient use of space: if all but a few index keys on a page have been deleted, the page remains allocated. Therefore, a usage pattern in which most, but not all, keys in each range are eventually deleted will see poor use of space. For such usage patterns, periodic reindexing is recommended."

I could imagine that the churn caused by re-importing the timetable could easily provoke such poor use of space.

We should add a cronjob that executes REINDEX DATABASE tfcweb monthly.