Doesn't work properly when git just initialized

[zommerfelds]

mkdir tmp
cd tmp
git init
touch hello
git add hello

Prints

2018/03/11 01:19:58 Failed to parse branch name for output: [## No commits yet on master]

Same for gs. git status works

[mroth]

Ah yes. Should be relatively simple to address by adding in ExtractBranch and adding a test case, if someone wants to take this on as a good introductory PR for the project!