• PHP >= 5.5.9

1. Download/clone and run composer install
2. Setup and run as a website (e.g. using MAMP)
3. Create a Slack app and a GitHub app. Set the redirect URI's to whatever address you setup in step 2
4. Rename .env.example to .env and fill in the required information

I recommend using Fluid to make it feel more like an "app" and add it to your dock. Point fluid to your web address and add an icon if you want.

Once the app is up and running you will need to authenticate with Slack and GitHub. Follow onscreen instructions.