Test Architecture Tweak

As I was starting to write tests for sync-fork, wanted to try and simplify the test architecture a little bit.
Tests now update the remote with a second repository instead of using local and resetting.
This was just easier for me to think about and more closely mirrors reality.

@kevgo what do you think?

Note: I used git-extract to pull this off my sync-fork branch.
I think it should use "current_branch" here, as read by https://github.com/Originate/git-town/blob/master/features/step_definitions/commit_steps.rb#L4

What makes you believe always specifying the branch name is better? In my view, using the current branch is more natural: "Given I am on a feature branch, and this commit exists". I'm not saying its wrong what you say, just want to hear your thought process.