Add merkle whitelist voting strategy

[Orland0x]

closes #382

[pscott]

I think we can add a bit more tests, and I think I'm missing why we need to sort the hashes :)

Also, is there an npm package that can take a hash_function as a parameter to build a merkletree?:)

[Orland0x]

I think we can add a bit more tests, and I think I'm missing why we need to sort the hashes :)

Also, is there an npm package that can take a hash_function as a parameter to build a merkletree?:)

If you dont sort the hashes, then you need an additional positional argument for each hash in order to reconstruct the root. So it seems like standard practice to do so.

Yeah there is a lib I tried to used called merkletreejs. I couldn't get it to work with pedersen though. Pedersen is unusual in that it takes 2 numbers and produces the hash whereas most hash functions concatenate the numbers (eg with abi.encode) then hash that single number.

Agreed about the tests - will add more. I basically just copied this implementation, so wasn't too worried about correctness. https://github.com/ncitron/cairo-merkle-distributor

[pscott]

All good ser!

utACK ;) (but CI will test for me :D)