gem install git-up no longer working in El Capitan

After upgrating to OS "El Capitan" I noticed that git-up was no longer installed. I tried to install by:

~ 🍺 gem install git-up
ERROR:  While executing gem ... (Errno::EACCES)
Permission denied - /Library/Ruby/Gems/2.0.0/gems/git-up-0.5.12/bin/git-up
~ 🍺

Mal El Capitan

Solution

After digging in I found the directory is owned by a user other than myself. (/Library/Ruby/Gems/.. is installed by Apple as part of Mac OS X.)

So I simply used brew to get install my own ruby and bingo!

~ 🍺 brew update
~ 🍺 brew install ruby

Then I could run:

~ 🍺 gem install git-up
...
6 gems installed

I started this post as a question but ended with a solution. I hope this helps.