shows "0%" when there's zero votes

Closes #97

app/helpers/application_helper.rb

@@ -5,7 +5,7 @@ module ApplicationHelper
   end
 
   def percentage(vote, debate)
-    return if debate.total_votes == 0
+    return "0%" if debate.total_votes == 0
     debate.send(vote).percent_of(debate.total_votes).to_s + "%"
   end
 

spec/features/votes_spec.rb

@@ -13,6 +13,20 @@ feature 'Votes' do
       visit debate_path(@debate)
     end
 
+    scenario 'Show no votes' do
+      visit debate_path(@debate)
+
+      expect(page).to have_content "0 votes"
+
+      within('#in_favor') do
+        expect(page).to have_content "0%"
+      end
+
+      within('#against')  do
+        expect(page).to have_content "0%"
+      end
+    end
+
     scenario 'Show' do
       vote = create(:vote, voter: @manuela, votable: @debate, vote_flag: true)
       vote = create(:vote, voter: @pablo, votable: @debate, vote_flag: false)