Proper deployment steps + next steps of learning RoR

I'm new to RoR and going through the tutorials trying to learn as much as
possible. I have actually two questions:

1. What is a proper way to deploy an app into the PROD environment? Here is
what I'm trying to avoid: when writing/testing application (ie. new user
signs ups) on my local machine, I don't want these users to be deployed into
the PROD environment along side.

That will not happen because users you add when running in development
mode will go into the development database on your local PC. When you
have deployed, the database is the production db on the server, which
will initially be empty.

2. I'm going through and when I finish-- what
should I pursue next?

That depends on what your aim is.