. It adds a " Generate Regtest Wallet" since Bitcoin Core v.021 does not automatically create new wallets on startup.
If the reader try to mine without a wallet, it will receive the erro: "No wallet is loaded. Load a wallet using loadwallet or create a new one with createwallet. (Note: A default wallet is no longer automatically created)"
. The command "bitcoin-cli -regtest generate" throws the error: " generate has been replaced by the -generate cli option.". So it fixes the command.
. "bitcoin-cli -regtest sendtoaddress" throws the error: "Fee estimation failed. Fallbackfee is disabled. Wait a few blocks or enable -fallbackfee.", so the "fallbackfee." is added to the bitcoind startup.