The use case

• The event ticket can be displayed on the user wallet
• A user can RSVP for friends (The friend still has to sign in on Kickback to receive a notification email and has to have eth to be able to withdraw)
• Even organisers can use Kickback NFT as token gated access on the Discord channel, etc.

Feature

• Each event (Conference) has its own NFT contract
• Contract supports either ERC721 or 1155
• Use Conference.participantsIndex as TokenId
• Metadata uri can be set at Conference constructor
• Metadata uri is set at Deployer and can be changed by groupAdmin. (Refer to changeClearFee for the similar implementation).
• The ticketing NFT cannot be transferred to the address which is already registered (if a user want to buy multiple tickets for friends, the user has to transfer to a different user address before purchasing the second ticket)

Acceptance scenario

Please make sure to write tests to cover at least these scenarios.

• When a user registers, ownerOf(tokenId) returns the registrant address.
• When a user registers, it emits a relevant event that NFT markets like OpenSea use to index.
• When a user transfer's NFT, it emits a relevant event that NFT markets like OpenSea use to index.
• When the registrant transfers the ticket to a recipient, isRegistered/isAttended/isPaid returns the info about the recipient (if this ended up causing too much attack vector, we may make the token not transferrable ).
• When the registrant transfer that ticket to a recipient, the user can register again (as the registrant is no longer registered for the event).
• When a user receives the NFT, the user cannot register as the user is already registered.
• When the registrant transfers the ticket to a recipient, the new recipient can call withdraw and clearAndSend to receive the payout