Cancel last action during night

[14chanwa]

Proposed solution to add this feature: at each turn, save a copy of the game in the database. Cancelling an action would consist in loading a previous version of the database.
This would also enable saving a game (or restoring it if app goes to background for too long)
Todo: implement a database that saves all the details of the night (hacker inspected who, mutant mutated who with what result, etc)