ActiveRecord model design help

I need some help on the following model design :

User model (user.rb)
class User < ActiveRecord::Base
has_many :analyses, :dependent => :destroy

Analysis model (analysis.rb)
class Analysis < ActiveRecord::Base
belongs_to :instructor, :class_name => “User”, :foreign_key
=> :instructor_id
belongs_to :member, :class_name => “User”, :foreign_key
=> :member_id

creating an analysis works
Analysis.create(:instructor_id => 1, :member_id => 2, :status =>
I can get :

User.find(1).analyses raise an error :
ActiveRecord::StatementInvalid: Mysql::Error: Unknown column
is there any way to handle this design ?

thanks a lot for your help

(btw I use the inflection plural analysis -> analyses)