I've made a few of them; there are some tricks -- especially if you want them to stay authenticated. AddToHome trick will reference the page they are currently on, so I only allow it on the /home or /dashboard like pages -- if they add to home from a deep-link it will always land them there.
And there's like a dozen meta tags for the Apple/Android systems to get right.
It basically creates a hosted-web-view with less "chrome" around there -- no address bar and stuff like that -- so you'll need to solve the 'back-button' problem too.
