Adding policies.pkgdef to VSIX 2013 Package to create Custom Checkin Policy

I am attempting to create a VSIX package based on this article: http://geekswithblogs.net/terje/archive/2012/03/10/packaging-custom-checkin-policies-for-visual-studio-using-vsix.aspx

However, the article seems quite outdated for Visual Studio 2013 since I do not see the option to add content to Visual Studio 2013, nor does the Content tag seem to be available in Intellisense when editing the manifest file directly.

Therefore, what is the proper method of packaging a custom check-in policy for Visual Studio 2013/TFS 2013 using a VSIX Package for Visual Studio 2013 Update 2?

Thanks.