Improve README with a better sample of connecting locally vs in production

[calvinkarundu]

I think it would be better if the README clearly indicated how to connect when running locally vs in production. Naturally, someone would try and use the provided example to run locally, but this doesn't have the .with_plaintext() connection option applied and attempts to connect with a TLS connection. A quick breakdown of TLS vs plaintext and when to use each can help avoid some confusion.