Update README to refelct migration from Heroku to Vercell

[theamarks]

Current readme instructions are for using Heroku cloud database. Because of website API needs, cloud database has been switched to Vercell.

• update for Vercell --> https://github.com/Seafood-Globalization-Lab/artis_database/blob/fdf0cd1fa54f5f46522ceac8d92f7e2f29431418/README.md?plain=1#L11-L71

Everything below will stay the same. Can be used for updating cloud or local database. https://github.com/Seafood-Globalization-Lab/artis_database/blob/fdf0cd1fa54f5f46522ceac8d92f7e2f29431418/README.md?plain=1#L72