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

app/validators/input_options_presence_validator.rb

@@ -2,7 +2,7 @@
 class InputOptionsPresenceValidator < ActiveModel::EachValidator
   def validate_each(record, attribute, value)
     return true unless record.input_type =~ /radio|check/i
-    return true if value.present? && value.count > 0
+    return true if value.present? && value.count.positive?
 
     record.errors[attribute] << (options[:message] ||
                                 "You must provide answer options for the selected input type.")

app/workers/quiz_status.rb

@@ -7,7 +7,7 @@ class QuizStatus
   end
 
   def started
-    candidate.answers.count > 0
+    candidate.answers.count.positive?
   end
 
   def on_summary