constructor({ transactionModel = TransactionStorage, coinModel = CoinStorage } = {}) {
    this.transactionModel = transactionModel;
    this.coinModel = coinModel;
  }
*************************************
** This migration script will fix historical instances
** of an issue where coins that were used in a now invalid
** tx are left with that txid as the spentTxid even
** though the coin is now unspent.
**
** This does a dry run by default. Use "--dryrun false"
** to execute outside of dry run.
** 
** Use the --chain [CHAIN] and --network [NETWORk] flags to 
** select the chain and network to run against.
** You must have valid RPC connection specified in bitcore.config.json.
******************************************