Best practice: should I use an AR Model or a global Hash for static data?

I'm thinking about a social networking-site. My user-model should have an attribute "eyecolor", which could be set on a view-page with a select-box/dropdownlist.

My question: -> should I make a AR-Model or should I use a global Hash/Constant for the data? Is there a best practice for "static-models"?

And how do I associate following without an AR-Model with relations:

u = User.first 
u.eyecolor 
==> 1 (not the eyecolor-string!)

What I need is the eyecolor-string:

u = User.first 
u.eyecolor 
==> "brown"

Thanks, sorry for my bad english!