rubocop noise: switched to predicate comparisons

Also introduced because of .ruby-version specification

http://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Style/NumericPredicate

app/controllers/candidate_controller.rb

@@ -12,7 +12,7 @@ class CandidateController < ApplicationController
   end
 
   def welcome
-    render :welcome_back if current_candidate.answers.count > 0
+    render :welcome_back if current_candidate.answers.count.positive?
   end
 
   def saved