Helpers to save/restore the DB data

Say you imported a lot of spreadsheets
Then created modified deleted a bunch of records.
Then you know the next thing you do will make a bug
even if you kill the database and restart it.

In that case kill the DB, save the data and next time you need to
reproduce the bug just restore the data.

```
SAVE=educ123 make save
make start
SAVE=educ123 make restore
```