Modify CFP to accept proposals for other things

Add field cfp_type and relevant validations
Add Program#cfp to preserve backwards compatibility
Add 'for_events' scope to the cfp, in order for it to be used like
program.cfps.events
Add useful methods
Add rspec test for the new code
The supported cfp types can be viewed via Cfp::TYPES

spec/models/cfp_spec.rb

@@ -1,8 +1,24 @@
 require 'spec_helper'
 
 describe Cfp do
+  subject { create(:cfp) }
   let!(:conference) { create(:conference, end_date: Date.today) }
-  let!(:cfp) { build(:cfp, start_date: Date.today - 2, end_date: Date.today - 1, program_id: conference.program.id) }
+  let!(:cfp) { create(:cfp, start_date: Date.today - 2, end_date: Date.today - 1, program_id: conference.program.id) }
+
+  describe 'scope' do
+    describe '#for_events' do
+      it 'returns the cfp for events' do
+        expect(conference.program.cfps.for_events).to be_a Cfp
+        expect(conference.program.cfps.for_events.cfp_type).to eq('events')
+      end
+    end
+  end
+
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:cfp_type) }
+    it { is_expected.to validate_inclusion_of(:cfp_type).in_array(Cfp::TYPES) }
+    it { is_expected.to validate_uniqueness_of(:cfp_type).scoped_to(:program_id).case_insensitive }
+  end
 
   describe '#before_end_of_conference' do
     describe 'fails to save cfp' do
@@ -97,4 +113,28 @@ describe Cfp do
       end
     end
   end
+
+  describe '#open?' do
+    context 'returns false' do
+      it 'when start and end dates are in the past' do
+        cfp.start_date = Date.current - 3
+        cfp.end_date = Date.current - 1
+        expect(cfp.open?).to eq(false)
+      end
+
+      it 'when start and end dates are in the future' do
+        cfp.start_date = Date.current + 1
+        cfp.end_date = Date.current + 3
+        expect(cfp.open?).to eq(false)
+      end
+    end
+
+    context 'returns true' do
+      it 'when start date is in the past and end date is in the future' do
+        cfp.start_date = Date.current - 1
+        cfp.end_date = Date.current + 1
+        expect(cfp.open?).to eq(true)
+      end
+    end
+  end
 end