Fix handling of newsletter checkbox at signup
What does this MR do?
The checkbox "signup to newsletter" handling in registration form was failed badly by myself :-) This fixes it (and by that the test that is already in master)
How confident are you it won't break things if deployed?
quite, tests work.
Links to related issues
- added a test, or explain why one is not needed/possible...
- no unrelated changes
- 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))