Ctor initializes database and reads existing data. @param folder_path - path to folder with chain files
Adds given block to the end of chain @param block - block to append to chain
Method that finds the last block in chain \return last block or null if it haven't found
Get last block \return last block in chain
Method that checks validity of chain \return true is chain is valid, false - otherwise
Last block in chain
Handler of chain blocks storage
\class HashChain Class stores dynamic info and handles local files of hash chain