Bring back the `commit_url` as it's used by CycleAnalytics

app/serializers/commit_entity.rb

@@ -3,6 +3,13 @@ class CommitEntity < API::Entities::RepoCommit
 
   expose :author, using: UserEntity
 
+  expose :commit_url do |commit|
+    namespace_project_tree_url(
+      request.project.namespace,
+      request.project,
+      id: commit.id)
+  end
+
   expose :commit_path do |commit|
     namespace_project_tree_path(
       request.project.namespace,

spec/serializers/commit_entity_spec.rb

@@ -35,6 +35,10 @@ describe CommitEntity do
     expect(subject).to include(:commit_path)
   end
 
+  it 'contains URL to commit' do
+    expect(subject).to include(:commit_url)
+  end
+
   it 'needs to receive project in the request' do
     expect(request).to receive(:project)
       .and_return(project)