This video was made for learn how to make animated model with rigify and import to the unity, and add final-ik.
Also this video tells you how to add a weapon in the rigify.
The script that I used is in the link here:
https://docs.google.com/file/d/0B0NLL...
And the script wasn't made by me, check this:
• Blender Rigify into Unity Mecanim
The script maker also made a plugin that do same thing with this, but to me that doesn't worked, so I used the script instead.
Used Blender 2.78c.