Adding template helper with config-file?

[Niklas Holmberg]

Hi,

I'm using a json config that I run the cli with.
svg-sprite --config=svg/config.json 'svg/**/*.svg'

I want to add a custom helper to use in mustache templates but I cant figure out how to add them under variables?

For example how do I add a helper to my config that makes a string upperCase and is used like this?
{{#upperCase}}{{name}}{{/upperCase}}

I cant't find any example that helps me :)
Thanks