Hi everyone 
Is there an easy/quick way to shut down the forum or stop posting for a certain period of time? Other than changing all categories settings.
Any help would be much appreciated!
Well, the easiest way is to setup your forum in read-only mode. This means that the site remains online and users can only read topics but can not interact (reply, open new topics, put Like etc).
Thanks Daniela can you tell me how to do that?
Nevermind! looked it up and found out.
Go to your https://your-site/admin/backups page and click the Enable read-only mode
You can also configure a global alert that tells users that the site is paused, so they stay quiet 
Ma (l’ho appena scoperto, cercando post simili su meta), bisogna AVVERTIRE IN GRANDI LETTERE che, una volta attivata questa modalità ‘Sola lettura’, se durante esperimenti o operazioni chiudi la scheda della finestra (incognito) o ti disconnetti per qualsiasi motivo, anche solo per 1 minuto, ALLORA NON C’È MODO DI RICONNETTERSI!
Sì, c’è, tramite la console di Rails:
Discourse.disable_readonly_mode(Discourse::USER_READONLY_MODE_KEY)