2 pt keep approx pick up time

Closes foodsharing-dev/issues0#2

What does this MR do?

The pick up time was deleted every time, the shop settings have been edited. This MR fixes this

How confident are you it won't break things if deployed?

Not very much as I do not understand the SQL stuff.

Links to related issues

issues0#2

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes (just a minor code style change)
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))