AI choice is detemined by the last digit of the Transaction ID.
0: Null - %90 of money return
1: Rock
2: Scissors
3: Paper
4: Rock
5: Scissors
6: Paper
7: Rock
8: Scissors
9: Paper
a: Rock
b: Scissors
c:Paper
d:Rock
e: Scissors
f: Paper
Win pays x 2
Lose : money lost - 0.001 SBD msg
Tie : %90 money return
Bet is fixed to 0.1 SBD.