function setExchangeRateETHToUSD(uint256 _rate, uint256 _decimals) onlyOwner public {
        
        
        
        
        
        
        
        
        require(uint256(strayToken.decimals()).add(2) >= _decimals.add(18));
        
        exchangeRateETHToUSD = _rate;
        decimalsETHToUSD = _decimals;
        rate = _rate.mul(exchangeRateUSDToToken);
        if (uint256(strayToken.decimals()) >= _decimals.add(18)) {
            rate = rate.mul(10 ** (uint256(strayToken.decimals()).sub(18).sub(_decimals)));
        } else {
            rate = rate.div(10 ** (_decimals.add(18).sub(uint256(strayToken.decimals()))));
        }
        
        mininumContributeWei = mininumPurchaseTokenQuantity.div(rate); 
        
        
        if (mininumContributeWei * rate < mininumPurchaseTokenQuantity)
            mininumContributeWei += 1;
            
        emit RateUpdated(rate, mininumContributeWei);
    }