将项目文件添加到TFS中的现有ASP.NET网站

I have an existing ASP.NET Web Site (targeting v4.5) in VS 2012, which is in source control and is used by several other developers. It does not have a project file associated with it in source control (we are using TFS). I am wanting to create a project file for this website and place it in source control. I have an existing ASP.NET Web Site (targeting