I’ve created a MacGap project that has some UI, CSS and Javascript. The javascript attempts to authenticate with the slack API using the token you insert. If you’re successful, that’s when the timer was supposed to start. That’s where I stopped.
In case you are curious what a MacGap project might look like, you can download the files here - I gotta warn you, it’s not pretty. You can run it by launching the project in XCode.