func: 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;
      }