Smart contract and RESTful API for our Cointree at PennApps XXIII. It is a hardhat project, so use it's respective commands to run. Contains two smart contracts: 1. Vault Smart Contract (takes in a company's MATIC from Polygon & metamask wallet, holds it, and distributes it to people who complete tasks through our app client) 2. NFT Smart contract (mints an NFT upon transaction to serve as immutable record of transactions). In the future, the NFT contract will be replaced with a parent-child contract structure where each company get their own child contract to serve as a proof of transcation in order to cut out high gas fees of minting NFT.