Gith is another word for "right," as in "correct." It replaced these words mainly because it is easier to type. May have originated from a typo the same way as common words such as teh or pwn.
JohnTheManNinja: ya steve, maybe ur gith afterall.
SteveO: well I am teh cool, jeez bro.
The word Githmi originated from the most sacred part of the world. If someone is called Githmi, they will be the most precious and trustworthy person u will ever meet. S/he will be loyal and the best girlfriend, fiancée and wife material!!
When u call some one Githmi, you know that they are the most trustworthy and talented.
GitHub is a website popular with programmers because they can publish their programs there and work with other people on the internet to help make the code even better. One feature is that people can fork code, which means that they can essentially copy the code and make whatever changes to it that they want without editing the actual code. It's kind of like a group project where people can do whatever they want.