attendee.rb

class Attendee < ActiveRecord::Base
  belongs_to :conference
  has_many :submissions, :foreign_key => "presenter_id"
  has_many :attendences, :foreign_key => "attendee_id", :class_name => "Submission"
end

gistfile2.txt

Conference
  has_many Sponsors
  has_many Locations
  has_many Tracks T(Locations)
  has_many Schedulings T(Locations)
  has_many Submissions
  has_many Attendees

Sponsor 
  belongs_to Conference

Location
  belongs_to Conference
  has_many Tracks
  has_many Schedulings T(Tracks)

Track
  belongs_to Location
  has_many Schedulings

Scheduling
  belongs_to Track
  belongs_to Submission

Attendee
  belongs_to Conference
  has_many Submissions
  belongs_to Submissions

Submission
  belongs_to Presenters (Attendees)
  has_many Attendees
  belongs_to Conference
  has_one Scheduling

submission.rb

class Submission < ActiveRecord::Base
  belongs_to :conference
  has_one :scheduling
  belongs_to :presenter, :class_name => "Attendee"
  belongs_to :attendee
end