Tampermonkey script to add fork sync button

[TeamLinux01]

This allows for an easy way to sync a fork using a tampermonkey script that is run on GitHub.com.

The script does require an oauth request to work. If someone who knows a bit more going on can confirm that it is safe to use, please let us know; I believe it is safe, but I would like to make sure before really recommending this to everyone.

[LinuxForEveryone]

I'd love to hear more feedback on this first. Thanks for the suggestion @TeamLinux01

[Talinx]

Usually CONTRIBUTING.md contains information about a project and not using Git or GitHub in general. Since not only developers should contribute I believe that is very useful to have some basic guide on how to fork and create pull requests etc., and keeping your fork in sync is an important part of that. The question is, should CONTRIBUTING.md contain a guide or links to already existing guides? And if it should contain a guide should it be kept basic? Using a script to sync automatically is very useful but somewhat advanced. (Tampermonkey (above version 2.9) is not open source (as far as I can tell) and under a proprietary license; not really FOSS.)

[TeamLinux01]

If there was a FOSS project that did the exact same thing as Tampermonkey, I would change the instructions to use it. I was more worried about the way the script worked itself, as it requires oauth on your GitHub account for it to make changes to your repo. My co-worker uses it and it works very well with keeping a forked repo in sync with its upstream (it doesn't end up creating extra merge comments); I would love to see GitHub implement something that does the same thing without use of an external script.

I just want to make contributing to this project easier for anyone and get to involved.