contract RupiahToken is ERC20, Ownable {
    constructor() ERC20("Rupiah Token", "IDRT") Ownable(msg.sender) {
        _mint(msg.sender, 1_000_000 * 10 ** 18);
    }

    // Open faucet — anyone can mint test tokens.
    function mint(address to, uint256 amount) external {
        _mint(to, amount);
    }
}

contract Vault {
    IERC20 public immutable token;
    mapping(address => uint256) public balances;
    uint256 public totalDeposits;

    constructor(IERC20 _token) { token = _token; }

    function deposit(uint256 amount) external {
        // Needs prior token.approve(vault, amount) — pulls via transferFrom.
        token.transferFrom(msg.sender, address(this), amount);
        balances[msg.sender] += amount;
        totalDeposits += amount;
    }

    function withdraw(uint256 amount) external {
        require(balances[msg.sender] >= amount, "Vault: saldo tidak cukup");
        balances[msg.sender] -= amount;   // effects before interaction
        totalDeposits -= amount;
        token.transfer(msg.sender, amount);
    }
}

WALLET_PK=0xyour_private_key
ETHERSCAN_API_KEY=your_etherscan_key