publish to facebook opt-in

[stefan2904]

The API will support get an option for facebook publishing. Users should be able to opt-in for a facebook publication of the uploaded incident (job will be done server-side)

see ios issue here: https://github.com/mgratzer/cleancity-ios/issues#issue/6

[mgratzer]

danke fürs posten, hatte vergessen es auch hie rein zu stellen :-)