新增：仓库贡献者行数查询接口

app/views/api/v1/projects/code_stats/index.json.jbuilder

@@ -0,0 +1,14 @@
+json.author_count @result_object["author_count"]
+json.commit_count @result_object["commit_count"]
+json.change_files @result_object["change_files"]
+json.additions @result_object["additions"]
+json.deletions @result_object["deletions"]
+json.commit_count_in_all_branches @result_object["commit_count_in_all_branches"]
+json.authors @result_object["authors"].each do |author| 
+  json.author do 
+    json.partial! 'api/v1/users/commit_user', locals: { user: render_cache_commit_author(author), name: author['name'] }
+  end  
+  json.commits author["commits"]
+  json.additions author["additions"]
+  json.deletions author["deletions"]
+end