Add prev/next links to reading list

app/models/reading_list.rb

@@ -5,6 +5,14 @@ def initialize(year = Time.now.year)
     @year = year
   end
 
+  def prev_year
+    @year - 1
+  end
+
+  def next_year
+    @year + 1
+  end
+
   def books
     @books ||= select_books
   end

app/views/reading_list/index.html.haml

@@ -1,4 +1,8 @@
-%h1= reading_list.year
+- content_for :header do
+  %nav.flex.justify-between.items-center.py-6.border-b-8.border-dark-gray
+    %p.m-0= link_to "prev", reading_list_path(reading_list.prev_year)
+    %h1.m-0= reading_list.year
+    %p.m-0= link_to "next", reading_list_path(reading_list.next_year)
 
 %p #{reading_list.books.count} books for #{number_with_delimiter reading_list.total_pages} pages at a pace of #{reading_list.pace} pages/day.
 

spec/models/reading_list_spec.rb

@@ -128,4 +128,11 @@ def table_of_books(year)
       end
     end
   end
+
+  describe "something" do
+    it "idk" do
+      reading_list = ReadingList.new(2020)
+      expect(reading_list.previous_year).to eq nil
+    end
+  end
 end