docs: Add info about Arbitrum deployment

README.md

@@ -264,9 +264,11 @@ Having to write the test cases in Solidity was probably a huge driver in getting
 
 ### Production Deployment
 
-<img src="documentation/readme-pics/polygon-eth.webp" alt="Foundry Logo" style="width:100%;max-height:300px;object-fit:contain;" />
+<img src="documentation/readme-pics/arbitrum-eth.webp" alt="Foundry Logo" style="width:100%;max-height:300px;object-fit:contain;" />
 
-Initially, I deployed this Smart Contract to [Sepolia Testnet](https://www.alchemy.com/overviews/sepolia-testnet). However the transactions were so slow, that I understood that realistically, noone would sit through this just to try out the Dapp. So I deployed it to [Polygon Mumbai Testnet](https://www.alchemy.com/overviews/mumbai-testnet). Gotta say, I'm super happy. The gas fees are really low, and the transactions are super quick. I hope the mainnet experience is the same!
+Initially, I deployed this Smart Contract to [Sepolia Testnet](https://www.alchemy.com/overviews/sepolia-testnet). However the transactions were so slow, that I understood that realistically, noone would sit through this just to try out the Dapp. So I deployed it to [Polygon Mumbai Testnet](https://www.alchemy.com/overviews/mumbai-testnet). ~~Gotta say, I'm super happy. The gas fees are really low, and the transactions are super quick. I hope the mainnet experience is the same!~~ Aaand they decided to deprecate Mumbai Testnet 😕. I tried migrating to Amoy, but polygonscan doesn't support it yet, and I wanted to keep using `forge script`'s verify functionality. Cardona-zkEVM testnet was also considered, but it doesn't support EIP1559 yet (and foundry doesn't recognize the `--chain` name either). 
+
+Finally I decided to go with Arbitrum Sepolia - native etherscan explorer, all the features of mainnet, nuff said.
 
 Deployments are done using Foundry's `forge script` tool. We source the secret keys from our cast wallet, for maximum security. [Thanks Patrick Collins!](https://www.youtube.com/watch?v=VQe7cIpaE54). The script itself is used as part of our Foundry tests, so we know it's legit.