better years links

app/controllers/categories_controller.rb

@@ -14,8 +14,9 @@ class CategoriesController < ApplicationController
     district = @school.district
     authenticate(district.name.downcase, "#{district.name.downcase}!")
     school_categories = SchoolCategory.for(@school, @category)
-    @years = school_categories.map(&:year)
+    @years = school_categories.map(&:year).map(&:to_i).sort
     @year = (params[:year] || @years.first).to_i
+    @years.delete(@year)
     @school_category = SchoolCategory.for(@school, @category).in(@year).first
     @child_school_categories = SchoolCategory.for_parent_category(@school, @category).valid
     @questions = @category.questions

app/views/layouts/_school_header.html.haml

@@ -8,9 +8,10 @@
         Data from
         = "#{@year - 1}-#{@year}"
         school year.
-        Show:
+        - if @years.present?
-        - @years.each do |year|
+          Show:
-          = link_to(year, school_category_path(@school_category.school, @school_category.category, year: year))
+          - @years.each do |year|
+            = link_to(year, school_category_path(@school_category.school, @school_category.category, year: year))
     - if @school.district.present?
       %p
         %strong District: