support tuple hooks

[qhwa]

Hi, there is a problem when deploying with Edeliver as hooks are defined in raw Elixir functions causing a syntax error in generated sys.confg.

After some digging, I find hooks defined as tuples in example app. Unfortunately this is not working in real code.

I made a wrapper to make it work. Please have a look if this helps? Thanks.

[trenpixster]

Thanks for this @qhwa! 👍