Accessing files outside of dotter directory

Hi, 

I wanted to access a file outside of my dotter directory (because it contains secrets)

At the moment I'm using 

{{ command_output "cat ../path/to/file/private.yml" }}

As a template inside my dotfiles. 

Is this the right approach? 

The other option is to symlink in a post-deploy hook. I'm not sure what's preferable. 