What can it do? How does it work?
If you're aware of Ethereum and how it functions, basically Ethereum is known to be turing complete in how it is programmed and smart contracts can be written that way by making use of a programming language called as Solidity. This wasn't the case in Bitcoin (it may be intentionally not turing complete -
https://en.bitcoin.it/wiki/Script) and hence something had to be built as a layer on top of Bitcoin to enable turing complete smart contracts. Rootstock enables this and runs as a sidechain while also facilitating support for handling more transactions than the Bitcoin blockchain (about 300 transactions per second in about 10-20 seconds). Basically since it's a sidechain you'll have a currency called as a Rootcoin which can be exchanged back and forth to Bitcoins. Hence if Rootstock allows people to create smart contracts, people can use it to sign contracts and prove that it exists as this relies on proof-of-existence which again is stored on the blockchain.
So think of the various smart contracts that you can create with it soon (Without any middleman). To create ICOs and digital tokens (new altcoins) based on the trust from the Bitcoin Blockchain network, A contract between you and the pharmacist and the doctor where in Pharmacy benefit managers are removed as a middle man (where they make an extra buck for nothing) -
https://www.prolifics.com/blog/healthcare-blockchain-how-smart-contracts-could-revolutionize-care-delivery or a basic smart contract between you and the seller with a fix terms of the contract defining when the contract should be deemed as "complete" and broadcasted on the blockchain (to prove that it exists) thus increasing "Trust".
Usually there are Oracles (Oracles make use of information that otherwise can't be accesses by the blockchain in order to validate a smart contract and to provide information to it) that handle providing information to the smart contract like - Price rates, information on seasonal harvesting weather conditions (in case a smart contract is created for selling turnips during a particular seasons to determine yield).
Here's a good article explaining it :
https://medium.com/novamining/rootstock-rsk-smart-contracts-on-bitcoin-9ef28e135193Their Wiki on Github provides information on how to create a smart contract :
https://github.com/rsksmart/rskj/wiki/Starting-with-RSK-Smart https://github.com/rsksmart/rskj/wiki/Creating-Smart-Contracts-in-RSK and
https://github.com/rsksmart/rskj/wiki (use the links on the right to navigate)
Additional reference:
https://www.youtube.com/watch?v=RPQD7-AOjMI (What does it mean to be Turning complete in a programming language?)
