Beginnings of load and save to database

There are many changes in this pull request, mostly to do with removing mocking code and replacing it with logic to load/save to database.

The database must be updated with the SQL in deploy. In addition, there is now the requirement for a new test database, buttonmen_test, which should also be generated with the same SQL.

The game logic should work now for Soldiers buttons up to and including the stage of swing value selection.

To 'play' a game up to swing value selection, you need to do the following:
- create two new players
- login as one of them
- create a new game between the two players
- go to overview.html to see all active games
- click on the game number to activate it
- go to choose_swing.html to choose the swing value