Add archive page for older LTS changelogs and update recent changelog page

content/changelog-stable-old/index.html.haml

@@ -0,0 +1,28 @@
+---
+layout: changelog
+title: Archived LTS Changelog
+show_ratings: false
+has_rss: false
+actions:
+  <a class="app-button app-button--primary app-mobile-hide" href="/changelog-stable">
+    <ion-icon name="arrow-back-circle-outline"></ion-icon>
+    Back to Recent LTS Changelog
+  </a>
+---
+
+.ratings
+  - # Load older changelogs (all except the most recent 25, ordered correctly)
+  - archived_changelogs = site.changelogs[:lts].reverse.drop(25)
+  - archived_changelogs.each do |release|
+    %div
+      = partial('../_partials/release-header.html.haml', :release => release, :url => 'changelog-stable-old')
+      - if release.changes
+        %div.app-releases__list__items
+          = partial('../_partials/changelog-changes.html.haml', :changes => release.changes)
+      - else
+        %p No notable changes for this release.
+
+.app-banner
+  This is the changelog archive. The changelog for recent releases can be found
+  %a{:href => '/changelog-stable/'}
+    in the main LTS changelog page.

content/changelog-stable/index.html.haml

@@ -11,22 +11,27 @@ actions:
 ---
 
 .ratings
-  - # source: https://github.com/jenkins-infra/jenkins.io/blob/master/content/_data/changelogs/lts.yml
-  - site.changelogs[:lts].reverse_each do | release |
+  - # Load the most recent 25 changelogs (latest first)
+  - recent_changelogs = site.changelogs[:lts].reverse.take(25)
+  - recent_changelogs.each do |release|
     - if Gem::Version.new(release.version) <= Gem::Version.new(site.jenkins.stable)
       %div
-        = partial('release-header.html.haml', :release => release, :url => 'changelog-stable')
-        - if release.changes and release.lts_changes and release.lts_baseline
+        = partial('../_partials/release-header.html.haml', :release => release, :url => 'changelog-stable')
+        - if release.changes && release.lts_changes && release.lts_baseline
           .app-releases__notable-changes{:style => "margin-top: 15px"}
-            -# TODO figure out how to get rid of this
             = "Changes since #{release.lts_baseline}"
-        %div.app-releases__list__items
-          = partial('changelog-changes.html.haml', :changes => release.changes)
+        - if release.changes
+          %div.app-releases__list__items
+            = partial('../_partials/changelog-changes.html.haml', :changes => release.changes)
 
-      - if release.changes and release.lts_changes
+      - if release.changes && release.lts_changes
         .app-releases__notable-changes
-          = "Notable changes since #{release.lts_predecessor}"
+          - if release.lts_predecessor
+            = "Notable changes since #{release.lts_predecessor}"
         %div.app-releases__list__items
-          = partial('changelog-changes.html.haml', :changes => release.lts_changes)
+          = partial('../_partials/changelog-changes.html.haml', :changes => release.lts_changes)
 
-  = partial('changelog-stable.html')
+.app-banner
+  The changelog of historical releases can be found
+  %a{:href => '/changelog-stable-old/'}
+    in the LTS changelog archive.