refactors notifications into concerns and shared examples

spec/models/poll/poll_spec.rb

@@ -1,9 +1,13 @@
 require 'rails_helper'
 
-describe :poll do
+describe Poll do
 
   let(:poll) { build(:poll) }
 
+  describe "Concerns" do
+    it_behaves_like "notifiable"
+  end
+
   describe "validations" do
     it "should be valid" do
       expect(poll).to be_valid
@@ -199,4 +203,5 @@ describe :poll do
     end
 
   end
+
 end