Stop parsing output of ls

Output of ls [should not be parsed](http://mywiki.wooledge.org/ParsingLs), it doesn't cause a _problem_ in our use, but it should be avoided in all applications as a general principle.

Code: https://github.com/advania/pass/blob/master/db/migrate.sh#L30

Likely solution:
```bash
for file in *.sql;
do
	something $file
done
```