Link project version to changelog if there is one.

app/models/repository.rb

@@ -122,7 +122,7 @@ class Repository
 
   def expire_cache
     %i(size branch_names tag_names commit_count graph_log
-       readme version contribution_guide).each do |key|
+       readme version contribution_guide changelog).each do |key|
       cache.expire(key)
     end
   end
@@ -203,6 +203,13 @@ class Repository
       end
     end
   end
+
+  def changelog
+    cache.fetch(:changelog) do
+      tree(:head).blobs.find do |file|
+        file.name =~ /^(changelog|history)/i
+      end
+    end
   end
 
   def head_commit

app/views/projects/show.html.haml

@@ -52,7 +52,8 @@
 
             - if @repository.version
               - version = @repository.version
-              = link_to namespace_project_blob_path(@project.namespace, @project, tree_join(@repository.root_ref, version.name)), class: 'btn btn-block' do
+              - detail_file = @repository.changelog.try(:name) || version.name
+              = link_to namespace_project_blob_path(@project.namespace, @project, tree_join(@repository.root_ref, detail_file)), class: 'btn btn-block' do
                 Version:
                 %span.count
                   = @repository.blob_by_oid(version.id).data