If you find a way to do so, you should ask user if he/she accepts it. Otherwise, that would be a bit too obtrusive.
There’s no good way to programmatically manipulate items in the Dock. This isn’t an accident. Apple consider the Dock setup to be something that the user controls, and apps shouldn’t be messing with it.
You’ll find lots of folks who ignore this advice and use various unsupported techniques to modify the Dock setup. You are, of course, free to do the same, but I’d caution you against that. To start, it’s unsupported and might break in weird ways in the future. Beyond that, it’ll make users grumpy. If the user has gone to the trouble of installing your app, they won’t have a problem finding it in the Applications directory, and they are also quite capable of adding your app to their Dock. Doing it for them isn’t a big win for most users, and it’s a big lose for some fraction of users, like myself, who will hate you forever if you monkey with our Dock (-:
Similar logic applies to the Desktop folder, and to the various recent items lists.
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Quinn “The Eskimo!”
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"