function withdrawStock() public 
    {
         require(joined[msg.sender] > 0);
         require(timeWithdrawstock < now);

         
         uint256 share = stock.mul(investments[msg.sender]).div(totalPot);
         uint256 currentWithDraw = withdraStock[msg.sender];
         
         if (share <= currentWithDraw) { revert(); }

         uint256 balance = share.sub(currentWithDraw);

         if ( balance > 0 ) {
            
            withdraStock[msg.sender] = currentWithDraw.add(balance);

            stock = stock.sub(balance);
            
            msg.sender.transfer(balance);
            emit WithdrawShare(msg.sender, balance);


         } 
     }