Git Diff

[InRe-Dan]

We would like to have an implementation of the git diff command, which allows users to see the differences in files between their current location and a different point in the git history. The functionality of this feature will be extremely similar to how GitHub shows you which lines have been added and removed between commits: example here

On the main Tab UI, there should be a "Compare" button which makes a window pop up that allows the user choose which branches on which remotes to compare. Once the user confirms the branches, this window will close and another will open which shows the differences (the output of git diff.
Ideally we would like to have red/green colour coding for removals and additions.
We can either copy the list view that GitHub has, or use different tabs to show differences between different files.

To implement this issue, you will need to read up on JGit's DiffCommand and use it in your code to get the output of Git Diff.
I recommend that you get familliar with the output of git diff on the command line, and how it is used.
This feature will require two new FXML files and corresponding controllers, additions to TabController.java
and tab.fxml, and it may also require some new libraries or dependencies to make processing the differences between files easy.