Write "Proof of Reddit" contract# US-1: As a Redditor I want to link (and update anytime) my u/<username> to a ethereum address #
## US-1 AT-1 ##
GIVEN a reddit user account and a directory r/ethereumproofs/,
WHEN I post an address to a the directory and submit r/ethereumproofs/<hash>/<address> to the smart contract function RedditRegister.update(<hash>,<address>)
THEN my reddit name and my address is inserted or updated into the Registry
# US-2: As a smart contract developer I want to lookup the address of a redditor #
## US-2 AT-1 ##
GIVEN a <name><address> pair in the registry
WHEN I access RedditRegister.lookupAddr(<username>)
THEN it returns me the actual address linked to the reddit username or 0x0
# US-3: As a smart contract developer I want to lookup the reddit username of an address #
## US-3 AT-1 ##
GIVEN a <name><address> pair in the registry
WHEN I access RedditRegister.lookupName(<address>)
THEN it returns me the actual username of the redditor