Emerald: track tokens

[pro-wh]

we already have the plumbing to run something on each erc20 Transfer event. this gathers them into a token_balances table.

details:

• transfers from the zero ethereum address count as mints
• transfers to the zero ethereum address count as burns
• addresses in the table are oasis addresses. look up ethereum addresses as needed in the address preimages table

other notes:

• this doesn't count holders. I'll ask about how to implement this
• there's no enforcement about starting from genesis-----you can start whenever, and you may have negative "balance" where it only shows the total of all in-minus-out during the time scanned
• no nothin done about contracts using erc20-compatible Transfer events in any wrong way

Ideas for this:

1. observe all token transfer events
2. maintain our own accounting of all-tokens-all-accounts balances
3. thusly serve list of token balances for account details
4. delete token,account records when balance hits zero
5. maintain our own accounting of how many nonzero-balance accounts there are for each token
6. thusly serve holders count for token details

[mitjat]

Nice!

[pro-wh]

oh shoot I used "contract address" in the struct but "token address" in the db

[pro-wh]

changed struct to call it 'token address'