Adds sponsor model

app/models/conference.rb

@@ -33,6 +33,7 @@ class Conference < ActiveRecord::Base
   has_many :vpositions, :dependent => :destroy
   has_many :vchoices, :dependent => :destroy
   has_many :sponsorship_levels, dependent: :destroy
+  has_many :sponsors, dependent: :destroy
 
   belongs_to :venue
 

app/models/sponsor.rb

@@ -0,0 +1,12 @@
+class Sponsor < ActiveRecord::Base
+  attr_accessible :name, :description, :website_url, :logo
+  belongs_to :sponsorship_level
+  belongs_to :conference
+  has_attached_file :logo,
+                    styles: { thumb: '100x100>', large: '300x300>' }
+
+  validates_attachment_content_type :logo,
+                                    content_type: [/jpg/, /jpeg/, /png/, /gif/],
+                                    size: { in: 0..500.kilobytes }
+  validates_presence_of :name, :website_url
+end

app/models/sponsorship_level.rb

@@ -2,4 +2,5 @@ class SponsorshipLevel < ActiveRecord::Base
   attr_accessible :title
   validates_presence_of :title
   belongs_to :conference
+  has_many :sponsors
 end