Add legacy route

Link to old leap release if there is on specified in config/releases.yml
Show a flash on the /legacy view to notify users that there is a more
recent version.

app/controllers/application_controller.rb

@@ -100,7 +100,7 @@ def set_releases_parameters
     @stable_version = current['stable_version']
     @testing_version = current['testing_version']
     @testing_state = current['testing_state']
-    @legacy_release = current['legacy_release']
+    @legacy_release = current['legacy_version']
   end
 
   def set_baseproject

app/controllers/distributions_controller.rb

@@ -1,5 +1,5 @@
 class DistributionsController < OBSController
-  before_action :set_releases_parameters, only: %i[index testing leap]
+  before_action :set_releases_parameters, only: %i[index testing leap legacy]
 
   # GET /distributions
   def index
@@ -34,4 +34,16 @@ def testing
     flash[:notice] = _('Help test the next version of openSUSE Leap!')
     render action: "leap-#{@testing_version}", layout: 'download'
   end
+
+  # GET /distributions/legacy
+  def legacy
+    @hide_search_box = true
+    unless @legacy_release
+      redirect_to '/', flash: { error: _("No legacy distribution available") }
+      return
+    end
+    @version = @legacy_release
+    flash.now[:notice] = _("There is a new version of openSUSE Leap <a href='/distributions/leap'>available</a>!")
+    render action: "leap-#{@legacy_release}", layout: 'download'
+  end
 end

app/views/distributions/leap-15.0.html.erb

@@ -108,11 +108,16 @@
           </div><!-- /.card -->
         </div><!-- /.card-deck -->
       </div><!-- /.tab-pane -->
-
     </div><!-- /.tab-content -->
-
+    <div class="mt-3">
+      <% if @legacy_release %>
+        <%= link_to _('Download previous openSUSE Leap release'),
+          legacy_distributions_path %>
+      <% end %>
+    </div>
   </div><!-- /.container -->
 
+
 </section>
 
 <section class="my-5">

app/views/distributions/leap-42.3.html.erb

@@ -134,6 +134,12 @@
         </div><!-- /.card-deck -->
       </div><!-- /#unofficial-ports.tab-pane -->
     </div><!-- /.tab-content -->
+    <div class="mt-3">
+      <% if @stable_version %>
+        <%= link_to _('Download latest openSUSE Leap release'),
+          leap_distributions_path %>
+      <% end %>
+    </div>
   </div><!-- /.container -->
 </section>
 

config/routes.rb

@@ -10,6 +10,7 @@
       get 'leap'
       get 'leap/ports', to: 'distributions#leap_ports'
       get 'testing'
+      get 'legacy'
     end
   end