515/better error handling

[LeonMatthes]

Closes #515

[LeonMatthes]

For some reason, the logger now seems to send all logs to the logfile, instead of STDOUT
I don't know why this is happening, but it's definitely not intended

This is now fixed by using a Formatter

[chrisma]

Thanks for the changes.
I could imagine that if an error occurs, it might occur multiple times in succession when using the application. This would result in the admin's notification list filling up with the same error multiple times.

It might be useful to prevent this behavior, by e.g.:

• adding a counter to the notification (Occurred X times) when the notification is still unread,
• or checking whether the last created notification is the same as the one being created currently and only updating the creation date of this last notification, instead of creating a new one

[chrisma]

Nice changes! Another test for the error display might be helpful. (+ See my previous comment)

[LeonMatthes]

Thanks for the changes.
I could imagine that if an error occurs, it might occur multiple times in succession when using the application. This would result in the admin's notification list filling up with the same error multiple times.
It might be useful to prevent this behavior, by e.g.:

adding a counter to the notification (Occurred X times) when the notification is still unread,
or checking whether the last created notification is the same as the one being created currently and only updating the creation date of this last notification, instead of creating a new one

I opted for the counter version. I think its more transparent.
This now also works for all notifications, not just error notifications.

[chrisma]

This "magic number" (i.e. the 60 seconds in the model) might be better suited for the AppSettings.

[chrisma]

#543