Describe business value of features in specs

@charlierudolph This is a preview of what I'm planning to do with all specs. Wanted to get your feedback before I invest a lot of time into this.

This helps understand WHY the feature exists. The steps then explain HOW the feature works.
This also helps formulate the value of Git Town to teams better.
Fixed to

    As a developer about to extract commits into a new branch
    I want to be told when I forget to provide the branch name
    So that I know how to do this correctly without having to read the manual.