Fixes rust start script

Kept getting this error:

There were two issues with the start script:

It was using the sh command, which would open a bash shell. In my case, it was trying to use the wrong version of mysql (homebrew version) whereas I was using DBngin, and the mysql command was pointing correctly in my zsh shell
It was assuming there was a password, which isn't the case locally, so passing -p without a password would prompt for one.

This PR uses the default computer shell, and conditionally passes the -p flag.

syntaxfm / website