Basic Blockchain

Implementation of a basic and private blockchain with REST APIs to expose functionalities

Proof of concept for storing star coordinates on-chain

The application will create a Genesis Block when we run the application.
The user will request the application to send a message to be signed using a Wallet and in this way verify the ownership over the wallet address. The message format will be: <WALLET_ADRESS>:${new Date().getTime().toString().slice(0,-3)}:starRegistry;
Once the user have the message the user can use a Wallet to sign the message.
The user will try to submit the Star object for that it will submit: wallet address, message, signature and the star object with the star information. The Start information will be formed in this format:
```
    "star": {
        "dec": "68° 52' 56.9",
        "ra": "16h 29m 1.0s",
        "story": "Tell me about this star"
        }
```
The application will verify if the time elapsed from the request ownership (the time is contained in the message) and the time when you submit the star is less than 5 minutes.
If everything is okay the star information will be stored in the block and added to the chain
The application will allow us to retrieve the Star objects belong to an owner (wallet address).

Run it using the command node app.js (Server Listening for port: 8000)
To create the Genesis block: http://localhost:8000/block/0
Make the first request of ownership sending your wallet address: http://localhost:8000/requestValidation
Sign the message with your Wallet using a bitcoin node or https://cryptotools.net/bitcoin and https://reinproject.org/bitcoin-signature-tool/#sign for the address and signature generation
Submit your Star: http://localhost:8000/submitstar
Retrieve Stars owned by the wallet: <http://localhost:8000/blocks/<WALLET_ADDRESS>>]
Validate the full chain: http://localhost:8000/blocks/chainValidation