Tools
https://remix.ethereum.org - compile and run (deploy) smart contract https://solidity.readthedocs.io/en/latest/index.html - Documentation solidity compiler http://ethdocs.org/en/latest/index.html - Documentation ethereum https://ropsten.etherscan.io/ - to follow contract addresses on Ropsten testnet
Thanks to mitsosf https://github.com/mitsosf/solidity-lottery