Update index.md

Author: Hitisha-G

public/content/developers/docs/smart-contracts/languages/index.md

@@ -33,6 +33,7 @@ Previous knowledge of programming languages, especially of JavaScript or Python,
 
 - [Documentation](https://docs.soliditylang.org/en/latest/)
 - [Solidity Language Portal](https://soliditylang.org/)
+- [Remix-IDE for Solidity](https://remix.ethereum.org/)
 - [Solidity by Example](https://docs.soliditylang.org/en/latest/solidity-by-example.html)
 - [GitHub](https://github.com/ethereum/solidity/)
 - [Solidity Gitter Chatroom](https://gitter.im/ethereum/solidity) bridged to [Solidity Matrix Chatroom](https://matrix.to/#/#ethereum_solidity:gitter.im)