Adds sponsorship levels model

app/models/conference.rb

@@ -31,6 +31,7 @@ class Conference < ActiveRecord::Base
   has_many :vdays, :dependent => :destroy
   has_many :vpositions, :dependent => :destroy
   has_many :vchoices, :dependent => :destroy
+  has_many :sponsorship_levels, dependent: :destroy
 
   belongs_to :venue
 

app/models/sponsorship_level.rb

@@ -0,0 +1,5 @@
+class SponsorshipLevel < ActiveRecord::Base
+  attr_accessible :title, :donation_amount
+  validates_presence_of :title
+  belongs_to :conference
+end