Introduce a CallForParticipation model

app/models/call_for_participation.rb

@@ -0,0 +1,3 @@
+class CallForParticipation < ActiveRecord::Base
+  belongs_to :conference
+end

app/models/conference.rb

@@ -11,7 +11,7 @@ class Conference < ActiveRecord::Base
   has_many :tracks
   has_many :halls
   has_many :events, through: :tracks
-
+  has_one :call_for_participation, dependent: :destroy
 
   accepts_nested_attributes_for :tracks, :halls, reject_if: :all_blank, allow_destroy: true
 

db/migrate/20150420154042_create_call_for_participations.rb

@@ -0,0 +1,11 @@
+class CreateCallForParticipations < ActiveRecord::Migration
+  def change
+    create_table :call_for_participations do |t|
+      t.references :conference, index: true, foreign_key: true
+      t.datetime :opens_at
+      t.datetime :closes_at
+
+      t.timestamps null: false
+    end
+  end
+end

spec/factories/call_for_participations.rb

@@ -0,0 +1,8 @@
+FactoryGirl.define do
+  factory :call_for_participation do
+    conference nil
+opens_at "2015-04-20 18:40:43"
+closes_at "2015-04-20 18:40:43"
+  end
+
+end

spec/models/call_for_participation_spec.rb

@@ -0,0 +1,9 @@
+require 'rails_helper'
+
+RSpec.describe CallForParticipation, type: :model do
+  it 'belongs to a conference' do
+    conference = create :conference
+    cfp = create(:call_for_participation, conference_id: conference.id)
+    expect(CallForParticipation.find(cfp.id).conference).to eq conference
+  end
+end

spec/models/conference_spec.rb

@@ -81,6 +81,26 @@ RSpec.describe Conference, :type => :model do
     end
   end
 
+  describe 'call for participation association' do
+    let(:conference) { build :conference }
+    let(:call_for_participation) { build :call_for_participation }
+
+    before(:each) do
+      conference.save
+      call_for_participation.conference = conference
+      call_for_participation.save
+    end
+
+    it 'has one call for participation' do
+      expect(conference.call_for_participation).to eq call_for_participation
+    end
+
+    it 'destroys the associated call for participation when destroyed' do
+      conference.destroy
+      expect { CallForParticipation.find(call_for_participation.id) }.to raise_exception ActiveRecord::RecordNotFound
+    end
+  end
+
   it 'accepts nested attributes for tracks' do
     track_attributes = build(:track, conference: nil).attributes
     conference = create :conference