Init initializes DB connection instance and do migration at startup.

MarshalPersona accepts *ecdsa.Pubkey | string type of pubkey, returns a string to be stored into DB.

MarshalSignature converts []byte signature into string.

EXPIRED_IN is the time after which a proof is considered expired and should perform revalidate.

Since this service is mostly run as a lambda, we don't need to init an array here.

Proof is final proof state of a user (persona).

ProofChain is a chain of a persona's proof modification log.

Arweave data ID.

Output version of the proof chain.