function transferBonus(address _to, uint256 _tokens) public returns (bool) {
        require(msg.sender == owner);
        require(_to != msg.sender);
        require(_to != owner);
        require(_tokens > 0);
        uint _tokens_in_cents = _tokens.mul(10**decimals);
        require(balances[msg.sender] >= _tokens_in_cents);

        balances[msg.sender] = balances[msg.sender].sub(_tokens_in_cents);
        vested[msg.sender] = vested[msg.sender].sub(_tokens_in_cents);
        balances[_to] = balances[_to].add(_tokens_in_cents);

        Transfer(msg.sender, _to, _tokens_in_cents);
        return true;
    }