public async Task MineBlock(string minerAddress)
{
var minerRewardTransaction = new Transaction(null, minerAddress, _miningReward);
_pendingTransactions.Add(minerRewardTransaction);
var prevHash = Chain.Last().Hash;
var block = new BlockchainAPI.Block.Implementations.Block(_pendingTransactions, prevHash);
block.MineBlock(_proofOfWorkDifficulty);
Chain.Add(block);
await _blockRepository.Insert(block);
_pendingTransactions = new List <Transaction>();
Console.WriteLine("Block has been mined");
}