Improve documentation

[brooke-heaton]

I'm not sure how to phrase this but I guess I'm looking for some better documentation on how to use this Extension IRL. I think this might provide some help to me in that I am looking to pass arguments into a Feature dynamically so that the Feature can test a specific scenario but for multiple authenticated user roles - I'd feed the user role to the Feature and have it run multiple times for multiple roles. I'm unclear form the ReadMe how this would work.