Why do so many gems end in fu?

Question

Why do so many gems end in fu?

Not that this make it clear to me, but here is what Google says "define: fu".

Answer 1

It is, as @meagar said, a play on 'kung-fu'. It's an old, old practice. A few plugins for the GIMP are called ***-fu, and you can hear people say that their vim-fu is strong, to say that someone is particularly skilled with vim.

Answer 2

It comes from a trend in the English language consisting on attaching the particle -fu to an activity, normally to indicate that it there's a certain degree of skill involved. You can use these constructions the same way you would refer to martial arts (kung-fu):

"His math-fu is impressive"

"Can you solve this by doing some of your planning-fu?"

I believe the first rails gem that had this "lingüistic feature" was technoweenie's attachment-fu. It was a very useful gem, so it became widely popular. So it was imitated in other gems.