LetSync

New features:
- Log in with Google.
- Participants are able to add side effects.
- Email send to participant and their partner when creating appointments.

Bugs fixed:
- Several bugs were fixed in functionality issues

Know bugs:
- Our story module does not allow the user to edit the text properly.
- Edit the strategies, the previous actions assigned to the strategy are deleted.
Push notifications do not redirect to the specific module, only to the application home.