function buy() payable public returns (bool){


        uint256 amount = msg.value.mul(buyExchangeRate);

        require(!stopBuy);
        require(amount <= balances[owner]);

        balances[owner] = balances[owner].sub(amount);
        balances[msg.sender] = balances[msg.sender].add(amount);

        soldSupply = soldSupply.add(amount);
        buySupply = buySupply.add(amount);

        Transfer(owner, msg.sender, amount);
        return true;
    }