Boot Chimera from GRUB menu

[F4LL3N]

I have a working installation of Ubuntu (it loads by default)
AND
A working installation of Yosemite (i can get to that by holding down F12 at startup and selecting to boot from my 'Install Yosemite' USB.

How do I add Chimera to the GRUB menu?

 

[Going Bald]

Forum search is your friend. This question gets asked and answered at least twice each year. Method differs depending on version of OS X, version of Linux and whether the 2 are installed on same drive or on separate drives.