The contract uses a PRNG function to pick a winner from an array of players
To gurantee a 100% fairness, the admin must compute the Keccak256 hash of a random string off-chain and set it at the creation of each lottery.
Once the hash for that lottery is set, it can't be changed. To provide more randomness, the admin can call the pickWinner()
whenever he wants.
forge init
forge build
forge test
forge script LotteryScript -s "deployTest()" --force --broadcast --verify
forge script LotteryScript -s "upgradeTest()" --force --broadcast --verify