func: function refundContributors() public ended() onlyOwner() {
      bids[winner] = 0; 
      for (uint i = 0; i < accountsList.length;  i++) {
        if (bids[accountsList[i]] > 0) {
          uint refundValue = bids[accountsList[i]];
          bids[accountsList[i]] = 0;
          accountsList[i].transfer(refundValue); 
        }
      }
    }